PATCH: jsonpath string methods: lower, upper, initcap, l/r/btrim, replace, split_part

From c5c2fca8a5b480181a28233d4f3cd4baedbf2ba3 Mon Sep 17 00:00:00 2001
From: Florents Tselai <florents.tselai@gmail.com>
Date: Wed, 14 May 2025 10:47:07 -0400
Subject: [PATCH v2] Rebase latest changes. jsonpath_scan.l white spacing was a
 bit tricky. Need to check in detail

---
 src/backend/utils/adt/jsonpath.c             | 176 ++++++++-
 src/backend/utils/adt/jsonpath_exec.c        | 189 +++++++++
 src/backend/utils/adt/jsonpath_gram.y        |  71 +++-
 src/backend/utils/adt/jsonpath_scan.l        |  41 ++
 src/include/utils/jsonpath.h                 |  22 ++
 src/test/regress/expected/jsonb_jsonpath.out | 393 +++++++++++++++++++
 src/test/regress/expected/jsonpath.out       |  72 ++++
 src/test/regress/sql/jsonb_jsonpath.sql      | 108 +++++
 src/test/regress/sql/jsonpath.sql            |  13 +
 9 files changed, 1081 insertions(+), 4 deletions(-)

diff --git a/src/backend/utils/adt/jsonpath.c b/src/backend/utils/adt/jsonpath.c
index 762f7e8a09d..646c7b460a3 100644
--- a/src/backend/utils/adt/jsonpath.c
+++ b/src/backend/utils/adt/jsonpath.c
@@ -326,6 +326,38 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 				*(int32 *) (buf->data + right) = chld - pos;
 			}
 			break;
+		case jpiReplaceFunc:
+		case jpiStrSplitPartFunc:
+		{
+			{
+				/*
+				 * First, reserve place for left/right arg's positions, then
+				 * record both args and sets actual position in reserved
+				 * places.
+				 */
+				int32		arg0 = reserveSpaceForItemPointer(buf);
+				int32		arg1 = reserveSpaceForItemPointer(buf);
+
+				if (!item->value.method_args.arg0)
+					chld = pos;
+				else if (!flattenJsonPathParseItem(buf, &chld, escontext,
+												   item->value.method_args.arg0,
+												   nestingLevel + argNestingLevel,
+												   insideArraySubscript))
+					return false;
+				*(int32 *) (buf->data + arg0) = chld - pos;
+
+				if (!item->value.method_args.arg1)
+					chld = pos;
+				else if (!flattenJsonPathParseItem(buf, &chld, escontext,
+												   item->value.method_args.arg1,
+												   nestingLevel + argNestingLevel,
+												   insideArraySubscript))
+					return false;
+				*(int32 *) (buf->data + arg1) = chld - pos;
+			}
+		}
+		break;
 		case jpiLikeRegex:
 			{
 				int32		offs;
@@ -362,6 +394,9 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 		case jpiTimeTz:
 		case jpiTimestamp:
 		case jpiTimestampTz:
+		case jpiStrLtrimFunc:
+		case jpiStrRtrimFunc:
+		case jpiStrBtrimFunc:
 			{
 				int32		arg = reserveSpaceForItemPointer(buf);
 
@@ -457,6 +492,9 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 		case jpiInteger:
 		case jpiNumber:
 		case jpiStringFunc:
+		case jpiStrLowerFunc:
+		case jpiStrUpperFunc:
+		case jpiStrInitcapFunc:
 			break;
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", item->type);
@@ -831,6 +869,72 @@ printJsonPathItem(StringInfo buf, JsonPathItem *v, bool inKey,
 			}
 			appendStringInfoChar(buf, ')');
 			break;
+		case jpiReplaceFunc:
+			appendStringInfoString(buf, ".replace(");
+			if (v->content.method_args.arg0)
+			{
+				jspGetArg0(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			if (v->content.method_args.arg1)
+			{
+				appendStringInfoChar(buf, ',');
+				jspGetArg1(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrSplitPartFunc:
+			appendStringInfoString(buf, ".split_part(");
+			if (v->content.method_args.arg0)
+			{
+				jspGetArg0(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			if (v->content.method_args.arg1)
+			{
+				appendStringInfoChar(buf, ',');
+				jspGetArg1(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrLowerFunc:
+			appendStringInfoString(buf, ".lower()");
+			break;
+		case jpiStrUpperFunc:
+			appendStringInfoString(buf, ".upper()");
+			break;
+		case jpiStrInitcapFunc:
+			appendStringInfoString(buf, ".initcap()");
+			break;
+		case jpiStrLtrimFunc:
+			appendStringInfoString(buf, ".ltrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrRtrimFunc:
+			appendStringInfoString(buf, ".rtrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrBtrimFunc:
+			appendStringInfoString(buf, ".btrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", v->type);
 	}
@@ -906,6 +1010,12 @@ jspOperationName(JsonPathItemType type)
 			return "number";
 		case jpiStringFunc:
 			return "string";
+		case jpiReplaceFunc:
+			return "replace";
+		case jpiStrLowerFunc:
+			return "lower";
+		case jpiStrUpperFunc:
+			return "upper";
 		case jpiTime:
 			return "time";
 		case jpiTimeTz:
@@ -914,6 +1024,16 @@ jspOperationName(JsonPathItemType type)
 			return "timestamp";
 		case jpiTimestampTz:
 			return "timestamp_tz";
+		case jpiStrLtrimFunc:
+			return "ltrim";
+		case jpiStrRtrimFunc:
+			return "rtrim";
+		case jpiStrBtrimFunc:
+			return "btrim";
+		case jpiStrInitcapFunc:
+			return "initcap";
+		case jpiStrSplitPartFunc:
+			return "split_part";
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", type);
 			return NULL;
@@ -1016,6 +1136,9 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 		case jpiInteger:
 		case jpiNumber:
 		case jpiStringFunc:
+		case jpiStrLowerFunc:
+		case jpiStrUpperFunc:
+		case jpiStrInitcapFunc:
 			break;
 		case jpiString:
 		case jpiKey:
@@ -1044,6 +1167,11 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 			read_int32(v->content.args.left, base, pos);
 			read_int32(v->content.args.right, base, pos);
 			break;
+		case jpiReplaceFunc:
+		case jpiStrSplitPartFunc:
+			read_int32(v->content.method_args.arg0, base, pos);
+			read_int32(v->content.method_args.arg1, base, pos);
+		break;
 		case jpiNot:
 		case jpiIsUnknown:
 		case jpiExists:
@@ -1055,6 +1183,9 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 		case jpiTimeTz:
 		case jpiTimestamp:
 		case jpiTimestampTz:
+		case jpiStrLtrimFunc:
+		case jpiStrRtrimFunc:
+		case jpiStrBtrimFunc:
 			read_int32(v->content.arg, base, pos);
 			break;
 		case jpiIndexArray:
@@ -1090,7 +1221,10 @@ jspGetArg(JsonPathItem *v, JsonPathItem *a)
 		   v->type == jpiTime ||
 		   v->type == jpiTimeTz ||
 		   v->type == jpiTimestamp ||
-		   v->type == jpiTimestampTz);
+		   v->type == jpiTimestampTz ||
+		   v->type == jpiStrLtrimFunc ||
+		   v->type == jpiStrRtrimFunc ||
+		   v->type == jpiStrBtrimFunc);
 
 	jspInitByBuffer(a, v->base, v->content.arg);
 }
@@ -1149,10 +1283,18 @@ jspGetNext(JsonPathItem *v, JsonPathItem *a)
 			   v->type == jpiInteger ||
 			   v->type == jpiNumber ||
 			   v->type == jpiStringFunc ||
+			   v->type == jpiReplaceFunc ||
+			   v->type == jpiStrLowerFunc ||
+			   v->type == jpiStrUpperFunc ||
 			   v->type == jpiTime ||
 			   v->type == jpiTimeTz ||
 			   v->type == jpiTimestamp ||
-			   v->type == jpiTimestampTz);
+			   v->type == jpiTimestampTz ||
+			   v->type == jpiStrLtrimFunc ||
+			   v->type == jpiStrRtrimFunc ||
+			   v->type == jpiStrBtrimFunc ||
+			   v->type == jpiStrInitcapFunc ||
+			   v->type == jpiStrSplitPartFunc);
 
 		if (a)
 			jspInitByBuffer(a, v->base, v->nextPos);
@@ -1184,6 +1326,24 @@ jspGetLeftArg(JsonPathItem *v, JsonPathItem *a)
 	jspInitByBuffer(a, v->base, v->content.args.left);
 }
 
+void
+jspGetArg0(JsonPathItem *v, JsonPathItem *a)
+{
+	Assert(v->type == jpiReplaceFunc ||
+			v->type == jpiStrSplitPartFunc);
+
+	jspInitByBuffer(a, v->base, v->content.method_args.arg0);
+}
+
+void
+jspGetArg1(JsonPathItem *v, JsonPathItem *a)
+{
+	Assert(v->type == jpiReplaceFunc ||
+			v->type == jpiStrSplitPartFunc);
+
+	jspInitByBuffer(a, v->base, v->content.method_args.arg1);
+}
+
 void
 jspGetRightArg(JsonPathItem *v, JsonPathItem *a)
 {
@@ -1206,6 +1366,7 @@ jspGetRightArg(JsonPathItem *v, JsonPathItem *a)
 	jspInitByBuffer(a, v->base, v->content.args.right);
 }
 
+
 bool
 jspGetBool(JsonPathItem *v)
 {
@@ -1227,7 +1388,8 @@ jspGetString(JsonPathItem *v, int32 *len)
 {
 	Assert(v->type == jpiKey ||
 		   v->type == jpiString ||
-		   v->type == jpiVariable);
+		   v->type == jpiVariable ||
+		   v->type == jpiStringFunc);
 
 	if (len)
 		*len = v->content.value.datalen;
@@ -1501,6 +1663,14 @@ jspIsMutableWalker(JsonPathItem *jpi, struct JsonPathMutableContext *cxt)
 			case jpiInteger:
 			case jpiNumber:
 			case jpiStringFunc:
+			case jpiReplaceFunc:
+			case jpiStrLowerFunc:
+			case jpiStrUpperFunc:
+			case jpiStrLtrimFunc:
+			case jpiStrRtrimFunc:
+			case jpiStrBtrimFunc:
+			case jpiStrInitcapFunc:
+			case jpiStrSplitPartFunc:
 				status = jpdsNonDateTime;
 				break;
 
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index dbab24737ef..51239121f18 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -301,6 +301,8 @@ static JsonPathExecResult executeNumericItemMethod(JsonPathExecContext *cxt,
 												   JsonValueList *found);
 static JsonPathExecResult executeDateTimeMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
 												JsonbValue *jb, JsonValueList *found);
+static JsonPathExecResult executeStringInternalMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
+												JsonbValue *jb, JsonValueList *found);
 static JsonPathExecResult executeKeyValueMethod(JsonPathExecContext *cxt,
 												JsonPathItem *jsp, JsonbValue *jb, JsonValueList *found);
 static JsonPathExecResult appendBoolResult(JsonPathExecContext *cxt,
@@ -1659,6 +1661,23 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
 			}
 			break;
 
+		case jpiStrLtrimFunc:
+		case jpiStrLowerFunc:
+		case jpiStrUpperFunc:
+		case jpiReplaceFunc:
+		case jpiStrRtrimFunc:
+		case jpiStrBtrimFunc:
+		case jpiStrInitcapFunc:
+		case jpiStrSplitPartFunc:
+		{
+			if (unwrap && JsonbType(jb) == jbvArray)
+				return executeItemUnwrapTargetArray(cxt, jsp, jb, found, false);
+
+			return executeStringInternalMethod(cxt, jsp, jb, found);
+		}
+		break;
+
+
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", jsp->type);
 	}
@@ -2792,6 +2811,176 @@ executeDateTimeMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
 	return executeNextItem(cxt, jsp, &elem, jb, found, hasNext);
 }
 
+/*
+ * Implementation of .upper(), lower() et. al. methods,
+ * that forward their actual implementation to internal functions.
+ */
+static JsonPathExecResult executeStringInternalMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
+												JsonbValue *jb, JsonValueList *found) {
+	Assert(	jsp->type == jpiStrLowerFunc ||
+			jsp->type == jpiStrUpperFunc ||
+			jsp->type == jpiReplaceFunc ||
+			jsp->type == jpiStrLtrimFunc ||
+			jsp->type == jpiStrRtrimFunc ||
+			jsp->type == jpiStrBtrimFunc ||
+			jsp->type == jpiStrInitcapFunc ||
+			jsp->type == jpiStrSplitPartFunc);
+	JsonbValue	jbvbuf;
+	bool		hasNext;
+	JsonPathExecResult res = jperNotFound;
+	JsonPathItem elem;
+	Datum		str; /* Datum representation for the current string value. The first argument to internal functions */
+	char		*tmp = NULL;
+	char		*resStr = NULL;
+
+	if (!(jb = getScalar(jb, jbvString)))
+		RETURN_ERROR(ereport(ERROR,
+							 (errcode(ERRCODE_INVALID_ARGUMENT_FOR_SQL_JSON_DATETIME_FUNCTION),
+							  errmsg("jsonpath item method .%s() can only be applied to a string",
+									 jspOperationName(jsp->type)))));
+
+	tmp = pnstrdup(jb->val.string.val, jb->val.string.len);
+	str = CStringGetTextDatum(tmp);
+
+	/* Internal string functions that accept no arguments */
+	switch (jsp->type)
+	{
+		case jpiStrLtrimFunc:
+		case jpiStrRtrimFunc:
+		case jpiStrBtrimFunc:
+		{
+			char	   *characters_str;
+			int			characters_len;
+			PGFunction	func = NULL;
+
+			switch (jsp->type)
+			{
+				case jpiStrLtrimFunc:
+					func = ltrim1;
+					break;
+				case jpiStrRtrimFunc:
+					func = rtrim1;
+					break;
+				case jpiStrBtrimFunc:
+					func = btrim1;
+					break;
+				default: ;
+			}
+
+			if (jsp->content.arg)
+			{
+				jspGetArg(jsp, &elem);
+				if (elem.type != jpiString)
+					elog(ERROR, "invalid jsonpath item type for .%s() argument", jspOperationName(jsp->type));
+
+				characters_str = jspGetString(&elem, &characters_len);
+				resStr = TextDatumGetCString(DirectFunctionCall2Coll(func,
+					DEFAULT_COLLATION_OID, str,
+					CStringGetTextDatum(characters_str)));
+				break;
+			}
+
+			resStr = TextDatumGetCString(DirectFunctionCall2Coll(func,
+					DEFAULT_COLLATION_OID, str,
+					CStringGetTextDatum(" ")));
+			break;
+		}
+
+		case jpiStrLowerFunc:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(lower, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiStrUpperFunc:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(upper, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiStrInitcapFunc:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(initcap, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiReplaceFunc:
+		{
+			char		*from_str, *to_str;
+			int			from_len, to_len;
+
+			jspGetArg0(jsp, &elem);
+			if (elem.type != jpiString)
+				elog(ERROR, "invalid jsonpath item type for .replace() from");
+
+			from_str = jspGetString(&elem, &from_len);
+
+			jspGetArg1(jsp, &elem);
+			if (elem.type != jpiString)
+				elog(ERROR, "invalid jsonpath item type for .replace() to");
+
+			to_str = jspGetString(&elem, &to_len);
+
+			resStr = TextDatumGetCString(DirectFunctionCall3Coll(replace_text,
+				C_COLLATION_OID,
+				CStringGetTextDatum(tmp),
+				CStringGetTextDatum(from_str),
+				CStringGetTextDatum(to_str)));
+			break;
+		}
+		case jpiStrSplitPartFunc:
+		{
+			char		*from_str;
+			Numeric		n;
+			int			from_len;
+
+			jspGetArg0(jsp, &elem);
+			if (elem.type != jpiString)
+				elog(ERROR, "invalid jsonpath item type for .split_part()");
+
+			from_str = jspGetString(&elem, &from_len);
+
+			jspGetArg1(jsp, &elem);
+			if (elem.type != jpiNumeric)
+				elog(ERROR, "invalid jsonpath item type for .split_part()");
+
+			n = jspGetNumeric(&elem);
+
+			resStr = TextDatumGetCString(DirectFunctionCall3Coll(split_part,
+				C_COLLATION_OID,
+				CStringGetTextDatum(tmp),
+				CStringGetTextDatum(from_str),
+				DirectFunctionCall1(numeric_int8, NumericGetDatum(n))));
+			break;
+		}
+		default:
+			elog(ERROR, "unsupported jsonpath item type: %d", jsp->type);
+	}
+
+	if (resStr)
+		res = jperOk;
+
+	hasNext = jspGetNext(jsp, &elem);
+
+	if (!hasNext && !found)
+		return res;
+
+	jb = hasNext ? &jbvbuf : palloc(sizeof(*jb));
+
+	/* Create the appropriate jb value to return */
+	switch (jsp->type)
+	{
+		/* Cases for functions that return text */
+		case jpiStrLowerFunc:
+		case jpiStrUpperFunc:
+		case jpiReplaceFunc:
+		case jpiStrLtrimFunc:
+		case jpiStrRtrimFunc:
+		case jpiStrBtrimFunc:
+		case jpiStrInitcapFunc:
+		case jpiStrSplitPartFunc:
+			jb->type = jbvString;
+			jb->val.string.val = resStr;
+			jb->val.string.len = strlen(jb->val.string.val);
+		default:
+			;
+			/* cant' happen */
+	}
+
+	return executeNextItem(cxt, jsp, &elem, jb, found, hasNext);
+}
+
 /*
  * Implementation of .keyvalue() method.
  *
diff --git a/src/backend/utils/adt/jsonpath_gram.y b/src/backend/utils/adt/jsonpath_gram.y
index 499745a8fef..c998c40cfbd 100644
--- a/src/backend/utils/adt/jsonpath_gram.y
+++ b/src/backend/utils/adt/jsonpath_gram.y
@@ -43,6 +43,9 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 							  JsonPathString *flags,
 							  JsonPathParseItem ** result,
 							  struct Node *escontext);
+static JsonPathParseItem *makeItemReplaceFunc(JsonPathParseItem *arg0, JsonPathParseItem *arg1);
+static JsonPathParseItem *makeItemStrSplitPartFunc(JsonPathParseItem *arg0, JsonPathParseItem *arg1);
+
 
 /*
  * Bison doesn't allocate anything that needs to live across parser calls,
@@ -86,6 +89,8 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 %token	<str>		DATETIME_P
 %token	<str>		BIGINT_P BOOLEAN_P DATE_P DECIMAL_P INTEGER_P NUMBER_P
 %token	<str>		STRINGFUNC_P TIME_P TIME_TZ_P TIMESTAMP_P TIMESTAMP_TZ_P
+%token	<str>		STR_REPLACEFUNC_P STR_LOWER_P STR_UPPER_P STR_LTRIM_P STR_RTRIM_P STR_BTRIM_P
+					STR_INITCAP_P STR_SPLIT_PART_P
 
 %type	<result>	result
 
@@ -94,8 +99,9 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 					index_elem starts_with_initial expr_or_predicate
 					datetime_template opt_datetime_template csv_elem
 					datetime_precision opt_datetime_precision
+					str_method_arg_elem
 
-%type	<elems>		accessor_expr csv_list opt_csv_list
+%type	<elems>		accessor_expr csv_list opt_csv_list str_method_arg_list
 
 %type	<indexs>	index_list
 
@@ -278,6 +284,32 @@ accessor_op:
 		{ $$ = makeItemUnary(jpiTimestamp, $4); }
 	| '.' TIMESTAMP_TZ_P '(' opt_datetime_precision ')'
 		{ $$ = makeItemUnary(jpiTimestampTz, $4); }
+	| '.' STR_REPLACEFUNC_P '(' str_method_arg_list ')'
+		{
+			if (list_length($4) == 2)
+				$$ = makeItemReplaceFunc(linitial($4), lsecond($4));
+			else
+				ereturn(escontext, false,
+						(errcode(ERRCODE_SYNTAX_ERROR),
+						 errmsg("invalid input syntax for type %s", "jsonpath"),
+						 errdetail(".replace() accepts two arguments.")));
+		}
+	| '.' STR_SPLIT_PART_P '(' str_method_arg_list ')'
+		{
+			if (list_length($4) == 2)
+				$$ = makeItemStrSplitPartFunc(linitial($4), lsecond($4));
+			else
+				ereturn(escontext, false,
+						(errcode(ERRCODE_SYNTAX_ERROR),
+						 errmsg("invalid input syntax for type %s", "jsonpath"),
+						 errdetail(".split_part() accepts two arguments.")));
+		}
+	| '.' STR_LTRIM_P '(' opt_datetime_template ')'
+		{ $$ = makeItemUnary(jpiStrLtrimFunc, $4); }
+	| '.' STR_RTRIM_P '(' opt_datetime_template ')'
+		{ $$ = makeItemUnary(jpiStrRtrimFunc, $4); }
+	| '.' STR_BTRIM_P '(' opt_datetime_template ')'
+		{ $$ = makeItemUnary(jpiStrBtrimFunc, $4); }
 	;
 
 csv_elem:
@@ -317,6 +349,15 @@ opt_datetime_template:
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
+str_method_arg_elem:
+	STRING_P						{ $$ = makeItemString(&$1); }
+	| INT_P							{ $$ = makeItemNumeric(&$1); }
+	;
+
+str_method_arg_list:
+	str_method_arg_elem							{ $$ = list_make1($1); }
+	| str_method_arg_list ',' str_method_arg_elem	{ $$ = lappend($1, $3); }
+	;
 key:
 	key_name						{ $$ = makeItemKey(&$1); }
 	;
@@ -357,6 +398,9 @@ key_name:
 	| TIME_TZ_P
 	| TIMESTAMP_P
 	| TIMESTAMP_TZ_P
+	| STR_LTRIM_P
+	| STR_RTRIM_P
+	| STR_BTRIM_P
 	;
 
 method:
@@ -373,6 +417,9 @@ method:
 	| INTEGER_P						{ $$ = jpiInteger; }
 	| NUMBER_P						{ $$ = jpiNumber; }
 	| STRINGFUNC_P					{ $$ = jpiStringFunc; }
+	| STR_LOWER_P					{ $$ = jpiStrLowerFunc; }
+	| STR_UPPER_P					{ $$ = jpiStrUpperFunc; }
+	| STR_INITCAP_P					{ $$ = jpiStrInitcapFunc; }
 	;
 %%
 
@@ -472,6 +519,28 @@ makeItemBinary(JsonPathItemType type, JsonPathParseItem *la, JsonPathParseItem *
 	return v;
 }
 
+static JsonPathParseItem *
+makeItemReplaceFunc(JsonPathParseItem *arg0, JsonPathParseItem *arg1)
+{
+	JsonPathParseItem *v = makeItemType(jpiReplaceFunc);
+
+	v->value.method_args.arg0 = arg0;
+	v->value.method_args.arg1 = arg1;
+
+	return v;
+}
+
+static JsonPathParseItem *
+makeItemStrSplitPartFunc(JsonPathParseItem *arg0, JsonPathParseItem *arg1)
+{
+	JsonPathParseItem *v = makeItemType(jpiStrSplitPartFunc);
+
+	v->value.method_args.arg0 = arg0;
+	v->value.method_args.arg1 = arg1;
+
+	return v;
+}
+
 static JsonPathParseItem *
 makeItemUnary(JsonPathItemType type, JsonPathParseItem *a)
 {
diff --git a/src/backend/utils/adt/jsonpath_scan.l b/src/backend/utils/adt/jsonpath_scan.l
index c7aab83eeb4..f20e9e5f1d3 100644
--- a/src/backend/utils/adt/jsonpath_scan.l
+++ b/src/backend/utils/adt/jsonpath_scan.l
@@ -433,6 +433,47 @@ static const JsonPathKeyword keywords[] = {
 	{9, false, TIMESTAMP_P, "timestamp"},
 	{10, false, LIKE_REGEX_P, "like_regex"},
 	{12, false, TIMESTAMP_TZ_P, "timestamp_tz"},
+	{ 2, false,	IS_P,		"is"},
+	{ 2, false,	TO_P,		"to"},
+	{ 3, false,	ABS_P,		"abs"},
+	{ 3, false,	LAX_P,		"lax"},
+	{ 4, false,	DATE_P,		"date"},
+	{ 4, false,	FLAG_P,		"flag"},
+	{ 4, false,	LAST_P,		"last"},
+	{ 4, true,	NULL_P,		"null"},
+	{ 4, false,	SIZE_P,		"size"},
+	{ 4, false,	TIME_P,		"time"},
+	{ 4, true,	TRUE_P,		"true"},
+	{ 4, false,	TYPE_P,		"type"},
+	{ 4, false,	WITH_P,		"with"},
+	{ 5, false, STR_BTRIM_P, "btrim"},
+	{ 5, true,	FALSE_P,	"false"},
+	{ 5, false,	FLOOR_P,	"floor"},
+	{ 5, false, STR_LOWER_P, "lower"},
+	{ 5, false, STR_LTRIM_P, "ltrim"},
+	{ 5, false, STR_RTRIM_P, "rtrim"},
+	{ 5, false, STR_UPPER_P, "upper"},
+	{ 6, false,	BIGINT_P,	"bigint"},
+	{ 6, false,	DOUBLE_P,	"double"},
+	{ 6, false,	EXISTS_P,	"exists"},
+	{ 6, false,	NUMBER_P,	"number"},
+	{ 6, false,	STARTS_P,	"starts"},
+	{ 6, false,	STRICT_P,	"strict"},
+	{ 6, false,	STRINGFUNC_P, "string"},
+	{ 7, false,	BOOLEAN_P,	"boolean"},
+	{ 7, false,	CEILING_P,	"ceiling"},
+	{ 7, false,	DECIMAL_P,	"decimal"},
+	{ 7, false, STR_INITCAP_P, "initcap"},
+	{ 7, false,	INTEGER_P,	"integer"},
+	{ 7, false, STR_REPLACEFUNC_P, "replace"},
+	{ 7, false,	TIME_TZ_P,	"time_tz"},
+	{ 7, false,	UNKNOWN_P,	"unknown"},
+	{ 8, false,	DATETIME_P,	"datetime"},
+	{ 8, false,	KEYVALUE_P,	"keyvalue"},
+	{ 9, false,	TIMESTAMP_P, "timestamp"},
+	{ 10,false, LIKE_REGEX_P, "like_regex"},
+	{ 10,false, STR_SPLIT_PART_P, "split_part"},
+	{ 12,false, TIMESTAMP_TZ_P, "timestamp_tz"},
 };
 
 /*
diff --git a/src/include/utils/jsonpath.h b/src/include/utils/jsonpath.h
index 23a76d233e9..4c60f9d1826 100644
--- a/src/include/utils/jsonpath.h
+++ b/src/include/utils/jsonpath.h
@@ -115,6 +115,14 @@ typedef enum JsonPathItemType
 	jpiTimeTz,					/* .time_tz() item method */
 	jpiTimestamp,				/* .timestamp() item method */
 	jpiTimestampTz,				/* .timestamp_tz() item method */
+	jpiReplaceFunc,				/* .replace() item method */
+	jpiStrLowerFunc,			/* .lower() item method */
+	jpiStrUpperFunc,			/* .upper() item method */
+	jpiStrLtrimFunc,			/* .ltrim() item method */
+	jpiStrRtrimFunc,			/* .rtrim() item method */
+	jpiStrBtrimFunc,			/* .btrim() item method */
+	jpiStrInitcapFunc,			/* .initcap() item method */
+	jpiStrSplitPartFunc,		/* .split_part() item method */
 } JsonPathItemType;
 
 /* XQuery regex mode flags for LIKE_REGEX predicate */
@@ -188,6 +196,12 @@ typedef struct JsonPathItem
 			int32		patternlen;
 			uint32		flags;
 		}			like_regex;
+
+		struct
+		{
+			int32		arg0;
+			int32		arg1;
+		}			method_args;
 	}			content;
 } JsonPathItem;
 
@@ -199,6 +213,8 @@ extern bool jspGetNext(JsonPathItem *v, JsonPathItem *a);
 extern void jspGetArg(JsonPathItem *v, JsonPathItem *a);
 extern void jspGetLeftArg(JsonPathItem *v, JsonPathItem *a);
 extern void jspGetRightArg(JsonPathItem *v, JsonPathItem *a);
+extern void jspGetArg0(JsonPathItem *v, JsonPathItem *a);
+extern void jspGetArg1(JsonPathItem *v, JsonPathItem *a);
 extern Numeric jspGetNumeric(JsonPathItem *v);
 extern bool jspGetBool(JsonPathItem *v);
 extern char *jspGetString(JsonPathItem *v, int32 *len);
@@ -266,6 +282,12 @@ struct JsonPathParseItem
 			uint32		len;
 			char	   *val;	/* could not be not null-terminated */
 		}			string;
+
+		struct
+		{
+			JsonPathParseItem *arg0;
+			JsonPathParseItem *arg1;
+		}			method_args;
 	}			value;
 };
 
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e91a29..2dbaec92129 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -2723,6 +2723,399 @@ select jsonb_path_query('"2023-08-15 12:34:56"', '$.timestamp().string()');
 (1 row)
 
 rollback;
+-- test .ltrim()
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('null', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('null', '$.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.ltrim()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('{}', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('true', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('1234', '$.ltrim().type()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim()');
+  jsonb_path_query_array  
+--------------------------
+ ["maybe  ", "yes", "no"]
+(1 row)
+
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .rtrim()
+select jsonb_path_query('"   hello   "', '$.rtrim(" ")');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.rtrim(" ")');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+-- test .btrim()
+select jsonb_path_query('"   hello   "', '$.btrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.btrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.btrim()');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.btrim()');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+-- test .lower()
+select jsonb_path_query('null', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('null', '$.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.lower()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('{}', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.lower()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.lower()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('true', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('1234', '$.lower().type()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower()');
+ jsonb_path_query_array 
+------------------------
+ ["maybe", "yes", "no"]
+(1 row)
+
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .upper()
+select jsonb_path_query('null', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('null', '$.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.upper()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('{}', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.upper()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.upper()');
+ jsonb_path_query 
+------------------
+ "1.23AAA"
+(1 row)
+
+select jsonb_path_query('1234', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('true', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('1234', '$.upper().type()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper()');
+ jsonb_path_query_array 
+------------------------
+ ["MAYBE", "YES", "NO"]
+(1 row)
+
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .initcap()
+select jsonb_path_query('null', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('null', '$.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.initcap()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('{}', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('true', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('1234', '$.initcap().type()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('["maybe yes", "probably no"]', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "Maybe Yes"
+ "Probably No"
+(2 rows)
+
+-- Test .replace()
+select jsonb_path_query('null', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('null', '$.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('["x", "y", "z"]', '$.replace("x", "bye")');
+ jsonb_path_query 
+------------------
+ "bye"
+ "y"
+ "z"
+(3 rows)
+
+select jsonb_path_query('{}', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('"hello world"', '$.replace("hello","bye")');
+ jsonb_path_query 
+------------------
+ "bye world"
+(1 row)
+
+select jsonb_path_query('"hello world"', '$.replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
+-- Test .split_part()
+select jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)');
+ jsonb_path_query 
+------------------
+ "def"
+(1 row)
+
+-- Test string methods play nicely together
+select jsonb_path_query('"hello world"', '$.replace("hello","bye").upper()');
+ jsonb_path_query 
+------------------
+ "BYE WORLD"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye")');
+ jsonb_path_query 
+------------------
+ "bye world"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.upper().lower().upper().replace("HELLO", "BYE")');
+ jsonb_path_query 
+------------------
+ "BYE WORLD"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
+select jsonb_path_query('"   hElLo WorlD "', '$.btrim().lower().upper().lower().replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
 -- Test .time()
 select jsonb_path_query('null', '$.time()');
 ERROR:  jsonpath item method .time() can only be applied to a string
diff --git a/src/test/regress/expected/jsonpath.out b/src/test/regress/expected/jsonpath.out
index fd9bd755f52..1b122e877d5 100644
--- a/src/test/regress/expected/jsonpath.out
+++ b/src/test/regress/expected/jsonpath.out
@@ -435,6 +435,78 @@ select '$.string()'::jsonpath;
  $.string()
 (1 row)
 
+select '$.replace("hello","bye")'::jsonpath;
+         jsonpath         
+--------------------------
+ $.replace("hello","bye")
+(1 row)
+
+select '$.lower()'::jsonpath;
+ jsonpath  
+-----------
+ $.lower()
+(1 row)
+
+select '$.upper()'::jsonpath;
+ jsonpath  
+-----------
+ $.upper()
+(1 row)
+
+select '$.lower().upper().lower().replace("hello","bye")'::jsonpath;
+                     jsonpath                     
+--------------------------------------------------
+ $.lower().upper().lower().replace("hello","bye")
+(1 row)
+
+select '$.ltrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.ltrim()
+(1 row)
+
+select '$.ltrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.ltrim("xyz")
+(1 row)
+
+select '$.rtrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.rtrim()
+(1 row)
+
+select '$.rtrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.rtrim("xyz")
+(1 row)
+
+select '$.btrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.btrim()
+(1 row)
+
+select '$.btrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.btrim("xyz")
+(1 row)
+
+select '$.initcap()'::jsonpath;
+  jsonpath   
+-------------
+ $.initcap()
+(1 row)
+
+select '$.split_part("~@~", 2)'::jsonpath;
+       jsonpath        
+-----------------------
+ $.split_part("~@~",2)
+(1 row)
+
 select '$.time()'::jsonpath;
  jsonpath 
 ----------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a5269..e229e0a0d04 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -623,6 +623,114 @@ select jsonb_path_query('"2023-08-15 12:34:56 +5:30"', '$.timestamp_tz().string(
 select jsonb_path_query('"2023-08-15 12:34:56"', '$.timestamp().string()');
 rollback;
 
+-- test .ltrim()
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+select jsonb_path_query('"   hello   "', '$.ltrim()');
+select jsonb_path_query('"   hello   "', '$.ltrim()');
+select jsonb_path_query('null', '$.ltrim()');
+select jsonb_path_query('null', '$.ltrim()', silent => true);
+select jsonb_path_query('[]', '$.ltrim()');
+select jsonb_path_query('[]', 'strict $.ltrim()');
+select jsonb_path_query('{}', '$.ltrim()');
+select jsonb_path_query('[]', 'strict $.ltrim()', silent => true);
+select jsonb_path_query('{}', '$.ltrim()', silent => true);
+select jsonb_path_query('1.23', '$.ltrim()');
+select jsonb_path_query('"1.23"', '$.ltrim()');
+select jsonb_path_query('"1.23aaa"', '$.ltrim()');
+select jsonb_path_query('1234', '$.ltrim()');
+select jsonb_path_query('true', '$.ltrim()');
+select jsonb_path_query('1234', '$.ltrim().type()');
+select jsonb_path_query('[2, true]', '$.ltrim()');
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim()');
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim().type()');
+
+-- test .rtrim()
+select jsonb_path_query('"   hello   "', '$.rtrim(" ")');
+select jsonb_path_query('"   hello   "', '$.rtrim(" ")');
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+
+-- test .btrim()
+select jsonb_path_query('"   hello   "', '$.btrim(" ")');
+select jsonb_path_query('"   hello   "', '$.btrim(" ")');
+select jsonb_path_query('"   hello   "', '$.btrim()');
+select jsonb_path_query('"   hello   "', '$.btrim()');
+
+-- test .lower()
+select jsonb_path_query('null', '$.lower()');
+select jsonb_path_query('null', '$.lower()', silent => true);
+select jsonb_path_query('[]', '$.lower()');
+select jsonb_path_query('[]', 'strict $.lower()');
+select jsonb_path_query('{}', '$.lower()');
+select jsonb_path_query('[]', 'strict $.lower()', silent => true);
+select jsonb_path_query('{}', '$.lower()', silent => true);
+select jsonb_path_query('1.23', '$.lower()');
+select jsonb_path_query('"1.23"', '$.lower()');
+select jsonb_path_query('"1.23aaa"', '$.lower()');
+select jsonb_path_query('1234', '$.lower()');
+select jsonb_path_query('true', '$.lower()');
+select jsonb_path_query('1234', '$.lower().type()');
+select jsonb_path_query('[2, true]', '$.lower()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower().type()');
+
+-- test .upper()
+select jsonb_path_query('null', '$.upper()');
+select jsonb_path_query('null', '$.upper()', silent => true);
+select jsonb_path_query('[]', '$.upper()');
+select jsonb_path_query('[]', 'strict $.upper()');
+select jsonb_path_query('{}', '$.upper()');
+select jsonb_path_query('[]', 'strict $.upper()', silent => true);
+select jsonb_path_query('{}', '$.upper()', silent => true);
+select jsonb_path_query('1.23', '$.upper()');
+select jsonb_path_query('"1.23"', '$.upper()');
+select jsonb_path_query('"1.23aaa"', '$.upper()');
+select jsonb_path_query('1234', '$.upper()');
+select jsonb_path_query('true', '$.upper()');
+select jsonb_path_query('1234', '$.upper().type()');
+select jsonb_path_query('[2, true]', '$.upper()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper().type()');
+
+-- test .initcap()
+select jsonb_path_query('null', '$.initcap()');
+select jsonb_path_query('null', '$.initcap()', silent => true);
+select jsonb_path_query('[]', '$.initcap()');
+select jsonb_path_query('[]', 'strict $.initcap()');
+select jsonb_path_query('{}', '$.initcap()');
+select jsonb_path_query('[]', 'strict $.initcap()', silent => true);
+select jsonb_path_query('{}', '$.initcap()', silent => true);
+select jsonb_path_query('1.23', '$.initcap()');
+select jsonb_path_query('"1.23"', '$.initcap()');
+select jsonb_path_query('"1.23aaa"', '$.initcap()');
+select jsonb_path_query('1234', '$.initcap()');
+select jsonb_path_query('true', '$.initcap()');
+select jsonb_path_query('1234', '$.initcap().type()');
+select jsonb_path_query('[2, true]', '$.initcap()');
+select jsonb_path_query('["maybe yes", "probably no"]', '$.initcap()');
+
+-- Test .replace()
+select jsonb_path_query('null', '$.replace("x", "bye")');
+select jsonb_path_query('null', '$.replace("x", "bye")', silent => true);
+select jsonb_path_query('["x", "y", "z"]', '$.replace("x", "bye")');
+select jsonb_path_query('{}', '$.replace("x", "bye")');
+select jsonb_path_query('[]', 'strict $.replace("x", "bye")', silent => true);
+select jsonb_path_query('{}', '$.replace("x", "bye")', silent => true);
+select jsonb_path_query('1.23', '$.replace("x", "bye")');
+select jsonb_path_query('"hello world"', '$.replace("hello","bye")');
+select jsonb_path_query('"hello world"', '$.replace("hello","bye") starts with "bye"');
+
+-- Test .split_part()
+select jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)');
+
+-- Test string methods play nicely together
+select jsonb_path_query('"hello world"', '$.replace("hello","bye").upper()');
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye")');
+select jsonb_path_query('"hElLo WorlD"', '$.upper().lower().upper().replace("HELLO", "BYE")');
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye") starts with "bye"');
+select jsonb_path_query('"   hElLo WorlD "', '$.btrim().lower().upper().lower().replace("hello","bye") starts with "bye"');
+
 -- Test .time()
 select jsonb_path_query('null', '$.time()');
 select jsonb_path_query('true', '$.time()');
diff --git a/src/test/regress/sql/jsonpath.sql b/src/test/regress/sql/jsonpath.sql
index 61a5270d4e8..8752ffcf08c 100644
--- a/src/test/regress/sql/jsonpath.sql
+++ b/src/test/regress/sql/jsonpath.sql
@@ -78,6 +78,19 @@ select '$.boolean()'::jsonpath;
 select '$.date()'::jsonpath;
 select '$.decimal(4,2)'::jsonpath;
 select '$.string()'::jsonpath;
+select '$.replace("hello","bye")'::jsonpath;
+select '$.lower()'::jsonpath;
+select '$.upper()'::jsonpath;
+select '$.lower().upper().lower().replace("hello","bye")'::jsonpath;
+select '$.ltrim()'::jsonpath;
+select '$.ltrim("xyz")'::jsonpath;
+select '$.rtrim()'::jsonpath;
+select '$.rtrim("xyz")'::jsonpath;
+select '$.btrim()'::jsonpath;
+select '$.btrim("xyz")'::jsonpath;
+select '$.initcap()'::jsonpath;
+select '$.split_part("~@~", 2)'::jsonpath;
+
 select '$.time()'::jsonpath;
 select '$.time(6)'::jsonpath;
 select '$.time_tz()'::jsonpath;
-- 
2.49.0

From 411a72f1d8654696b81a2386169a46ff67d3a818 Mon Sep 17 00:00:00 2001
From: Florents Tselai <florents.tselai@gmail.com>
Date: Sat, 24 May 2025 17:33:56 -0400
Subject: [PATCH v3] Add additional jsonpath string methods

Add the following jsonpath methods:

*   l/r/btrim()
*   lower(), upper()
*   initcap()
*   replace()
*   split_part()

Each simply dispatches to the standard string processing functions.
These depend on the locale, but since it's set at `initdb`, they can be
considered immutable and therefore allowed in any jsonpath expression.
---
 doc/src/sgml/func.sgml                       | 171 ++++++++
 src/backend/utils/adt/jsonpath.c             | 176 ++++++++-
 src/backend/utils/adt/jsonpath_exec.c        | 189 +++++++++
 src/backend/utils/adt/jsonpath_gram.y        |  71 +++-
 src/backend/utils/adt/jsonpath_scan.l        |  41 ++
 src/include/utils/jsonpath.h                 |  22 ++
 src/test/regress/expected/jsonb_jsonpath.out | 393 +++++++++++++++++++
 src/test/regress/expected/jsonpath.out       |  72 ++++
 src/test/regress/sql/jsonb_jsonpath.sql      | 108 +++++
 src/test/regress/sql/jsonpath.sql            |  13 +
 10 files changed, 1252 insertions(+), 4 deletions(-)

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index c67688cbf5f..25d0d920dbf 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -18627,6 +18627,177 @@ ERROR:  jsonpath member accessor can only be applied to an object
         <returnvalue>[{"id": 0, "key": "x", "value": "20"}, {"id": 0, "key": "y", "value": 32}]</returnvalue>
        </para></entry>
       </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>lower()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String converted to all lower case according to the rules of the database's locale.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"TOM"', '$.lower()')</literal>
+        <returnvalue>"tom"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>upper()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String converted to all upper case according to the rules of the database's locale.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"tom"', '$.upper()')</literal>
+        <returnvalue>"TOM"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>initcap()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the first letter of each word converted to upper case
+        according to the rules of the database's locale. Words are sequences
+        of alphanumeric characters separated by non-alphanumeric characters.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"hi THOMAS"', '$.initcap()')</literal>
+        <returnvalue>"Hi Thomas"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>replace(<replaceable>from</replaceable>, <replaceable>to</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with all occurrences of substring from replaced with substring to.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"abcdefabcdef"', '$.replace("cd", "XX")')</literal>
+        <returnvalue>"abXXefabXXef"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>split_part(<replaceable>delimiter</replaceable>, <replaceable>n</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String split at occurrences of <replaceable>delimiter</replaceable>
+        and returns the <replaceable>n</replaceable>'th field (counting from
+        one) or, when <replaceable>n</replaceable> is negative, returns the
+        |<replaceable>n</replaceable>|'th-from-last field.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)')</literal>
+        <returnvalue>"def"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"abc,def,ghi,jkl"', '$.split_part(",", 2)')</literal>
+        <returnvalue>"ghi"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>ltrim()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with spaces removed from the start of <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal> jsonb_path_query('"  hello"', '$.ltrim()')</literal>
+        <returnvalue>"hello"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>ltrim(<replaceable>characters</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the longest string containing only characters in
+        <replaceable>characters</replaceable> removed from the start of
+        <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"zzzytest"', '$.ltrim("xyz")')</literal>
+        <returnvalue>"test"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>rtrim()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with spaces removed from the end of <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"hello  "', '$.rtrim()')</literal>
+        <returnvalue>"hello"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>rtrim(<replaceable>characters</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the longest string containing only characters in
+        <replaceable>characters</replaceable> removed from the end of
+        <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"testxxzx"', '$.rtrim("xyz")')</literal>
+        <returnvalue>"test"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>btrim()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with spaces removed from the start and end of
+        <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"  hello  "', '$.btrim()')</literal>
+        <returnvalue>"hello"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>btrim(<replaceable>characters</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the longest string containing only characters in
+        <replaceable>characters</replaceable> removed from the start and end
+        of <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"xyxtrimyyx"', '$.btrim("xyz")')</literal>
+        <returnvalue>"trim"</returnvalue>
+       </para></entry>
+      </row>
+
      </tbody>
     </tgroup>
    </table>
diff --git a/src/backend/utils/adt/jsonpath.c b/src/backend/utils/adt/jsonpath.c
index 762f7e8a09d..646c7b460a3 100644
--- a/src/backend/utils/adt/jsonpath.c
+++ b/src/backend/utils/adt/jsonpath.c
@@ -326,6 +326,38 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 				*(int32 *) (buf->data + right) = chld - pos;
 			}
 			break;
+		case jpiReplaceFunc:
+		case jpiStrSplitPartFunc:
+		{
+			{
+				/*
+				 * First, reserve place for left/right arg's positions, then
+				 * record both args and sets actual position in reserved
+				 * places.
+				 */
+				int32		arg0 = reserveSpaceForItemPointer(buf);
+				int32		arg1 = reserveSpaceForItemPointer(buf);
+
+				if (!item->value.method_args.arg0)
+					chld = pos;
+				else if (!flattenJsonPathParseItem(buf, &chld, escontext,
+												   item->value.method_args.arg0,
+												   nestingLevel + argNestingLevel,
+												   insideArraySubscript))
+					return false;
+				*(int32 *) (buf->data + arg0) = chld - pos;
+
+				if (!item->value.method_args.arg1)
+					chld = pos;
+				else if (!flattenJsonPathParseItem(buf, &chld, escontext,
+												   item->value.method_args.arg1,
+												   nestingLevel + argNestingLevel,
+												   insideArraySubscript))
+					return false;
+				*(int32 *) (buf->data + arg1) = chld - pos;
+			}
+		}
+		break;
 		case jpiLikeRegex:
 			{
 				int32		offs;
@@ -362,6 +394,9 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 		case jpiTimeTz:
 		case jpiTimestamp:
 		case jpiTimestampTz:
+		case jpiStrLtrimFunc:
+		case jpiStrRtrimFunc:
+		case jpiStrBtrimFunc:
 			{
 				int32		arg = reserveSpaceForItemPointer(buf);
 
@@ -457,6 +492,9 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 		case jpiInteger:
 		case jpiNumber:
 		case jpiStringFunc:
+		case jpiStrLowerFunc:
+		case jpiStrUpperFunc:
+		case jpiStrInitcapFunc:
 			break;
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", item->type);
@@ -831,6 +869,72 @@ printJsonPathItem(StringInfo buf, JsonPathItem *v, bool inKey,
 			}
 			appendStringInfoChar(buf, ')');
 			break;
+		case jpiReplaceFunc:
+			appendStringInfoString(buf, ".replace(");
+			if (v->content.method_args.arg0)
+			{
+				jspGetArg0(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			if (v->content.method_args.arg1)
+			{
+				appendStringInfoChar(buf, ',');
+				jspGetArg1(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrSplitPartFunc:
+			appendStringInfoString(buf, ".split_part(");
+			if (v->content.method_args.arg0)
+			{
+				jspGetArg0(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			if (v->content.method_args.arg1)
+			{
+				appendStringInfoChar(buf, ',');
+				jspGetArg1(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrLowerFunc:
+			appendStringInfoString(buf, ".lower()");
+			break;
+		case jpiStrUpperFunc:
+			appendStringInfoString(buf, ".upper()");
+			break;
+		case jpiStrInitcapFunc:
+			appendStringInfoString(buf, ".initcap()");
+			break;
+		case jpiStrLtrimFunc:
+			appendStringInfoString(buf, ".ltrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrRtrimFunc:
+			appendStringInfoString(buf, ".rtrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrBtrimFunc:
+			appendStringInfoString(buf, ".btrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", v->type);
 	}
@@ -906,6 +1010,12 @@ jspOperationName(JsonPathItemType type)
 			return "number";
 		case jpiStringFunc:
 			return "string";
+		case jpiReplaceFunc:
+			return "replace";
+		case jpiStrLowerFunc:
+			return "lower";
+		case jpiStrUpperFunc:
+			return "upper";
 		case jpiTime:
 			return "time";
 		case jpiTimeTz:
@@ -914,6 +1024,16 @@ jspOperationName(JsonPathItemType type)
 			return "timestamp";
 		case jpiTimestampTz:
 			return "timestamp_tz";
+		case jpiStrLtrimFunc:
+			return "ltrim";
+		case jpiStrRtrimFunc:
+			return "rtrim";
+		case jpiStrBtrimFunc:
+			return "btrim";
+		case jpiStrInitcapFunc:
+			return "initcap";
+		case jpiStrSplitPartFunc:
+			return "split_part";
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", type);
 			return NULL;
@@ -1016,6 +1136,9 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 		case jpiInteger:
 		case jpiNumber:
 		case jpiStringFunc:
+		case jpiStrLowerFunc:
+		case jpiStrUpperFunc:
+		case jpiStrInitcapFunc:
 			break;
 		case jpiString:
 		case jpiKey:
@@ -1044,6 +1167,11 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 			read_int32(v->content.args.left, base, pos);
 			read_int32(v->content.args.right, base, pos);
 			break;
+		case jpiReplaceFunc:
+		case jpiStrSplitPartFunc:
+			read_int32(v->content.method_args.arg0, base, pos);
+			read_int32(v->content.method_args.arg1, base, pos);
+		break;
 		case jpiNot:
 		case jpiIsUnknown:
 		case jpiExists:
@@ -1055,6 +1183,9 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 		case jpiTimeTz:
 		case jpiTimestamp:
 		case jpiTimestampTz:
+		case jpiStrLtrimFunc:
+		case jpiStrRtrimFunc:
+		case jpiStrBtrimFunc:
 			read_int32(v->content.arg, base, pos);
 			break;
 		case jpiIndexArray:
@@ -1090,7 +1221,10 @@ jspGetArg(JsonPathItem *v, JsonPathItem *a)
 		   v->type == jpiTime ||
 		   v->type == jpiTimeTz ||
 		   v->type == jpiTimestamp ||
-		   v->type == jpiTimestampTz);
+		   v->type == jpiTimestampTz ||
+		   v->type == jpiStrLtrimFunc ||
+		   v->type == jpiStrRtrimFunc ||
+		   v->type == jpiStrBtrimFunc);
 
 	jspInitByBuffer(a, v->base, v->content.arg);
 }
@@ -1149,10 +1283,18 @@ jspGetNext(JsonPathItem *v, JsonPathItem *a)
 			   v->type == jpiInteger ||
 			   v->type == jpiNumber ||
 			   v->type == jpiStringFunc ||
+			   v->type == jpiReplaceFunc ||
+			   v->type == jpiStrLowerFunc ||
+			   v->type == jpiStrUpperFunc ||
 			   v->type == jpiTime ||
 			   v->type == jpiTimeTz ||
 			   v->type == jpiTimestamp ||
-			   v->type == jpiTimestampTz);
+			   v->type == jpiTimestampTz ||
+			   v->type == jpiStrLtrimFunc ||
+			   v->type == jpiStrRtrimFunc ||
+			   v->type == jpiStrBtrimFunc ||
+			   v->type == jpiStrInitcapFunc ||
+			   v->type == jpiStrSplitPartFunc);
 
 		if (a)
 			jspInitByBuffer(a, v->base, v->nextPos);
@@ -1184,6 +1326,24 @@ jspGetLeftArg(JsonPathItem *v, JsonPathItem *a)
 	jspInitByBuffer(a, v->base, v->content.args.left);
 }
 
+void
+jspGetArg0(JsonPathItem *v, JsonPathItem *a)
+{
+	Assert(v->type == jpiReplaceFunc ||
+			v->type == jpiStrSplitPartFunc);
+
+	jspInitByBuffer(a, v->base, v->content.method_args.arg0);
+}
+
+void
+jspGetArg1(JsonPathItem *v, JsonPathItem *a)
+{
+	Assert(v->type == jpiReplaceFunc ||
+			v->type == jpiStrSplitPartFunc);
+
+	jspInitByBuffer(a, v->base, v->content.method_args.arg1);
+}
+
 void
 jspGetRightArg(JsonPathItem *v, JsonPathItem *a)
 {
@@ -1206,6 +1366,7 @@ jspGetRightArg(JsonPathItem *v, JsonPathItem *a)
 	jspInitByBuffer(a, v->base, v->content.args.right);
 }
 
+
 bool
 jspGetBool(JsonPathItem *v)
 {
@@ -1227,7 +1388,8 @@ jspGetString(JsonPathItem *v, int32 *len)
 {
 	Assert(v->type == jpiKey ||
 		   v->type == jpiString ||
-		   v->type == jpiVariable);
+		   v->type == jpiVariable ||
+		   v->type == jpiStringFunc);
 
 	if (len)
 		*len = v->content.value.datalen;
@@ -1501,6 +1663,14 @@ jspIsMutableWalker(JsonPathItem *jpi, struct JsonPathMutableContext *cxt)
 			case jpiInteger:
 			case jpiNumber:
 			case jpiStringFunc:
+			case jpiReplaceFunc:
+			case jpiStrLowerFunc:
+			case jpiStrUpperFunc:
+			case jpiStrLtrimFunc:
+			case jpiStrRtrimFunc:
+			case jpiStrBtrimFunc:
+			case jpiStrInitcapFunc:
+			case jpiStrSplitPartFunc:
 				status = jpdsNonDateTime;
 				break;
 
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index dbab24737ef..51239121f18 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -301,6 +301,8 @@ static JsonPathExecResult executeNumericItemMethod(JsonPathExecContext *cxt,
 												   JsonValueList *found);
 static JsonPathExecResult executeDateTimeMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
 												JsonbValue *jb, JsonValueList *found);
+static JsonPathExecResult executeStringInternalMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
+												JsonbValue *jb, JsonValueList *found);
 static JsonPathExecResult executeKeyValueMethod(JsonPathExecContext *cxt,
 												JsonPathItem *jsp, JsonbValue *jb, JsonValueList *found);
 static JsonPathExecResult appendBoolResult(JsonPathExecContext *cxt,
@@ -1659,6 +1661,23 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
 			}
 			break;
 
+		case jpiStrLtrimFunc:
+		case jpiStrLowerFunc:
+		case jpiStrUpperFunc:
+		case jpiReplaceFunc:
+		case jpiStrRtrimFunc:
+		case jpiStrBtrimFunc:
+		case jpiStrInitcapFunc:
+		case jpiStrSplitPartFunc:
+		{
+			if (unwrap && JsonbType(jb) == jbvArray)
+				return executeItemUnwrapTargetArray(cxt, jsp, jb, found, false);
+
+			return executeStringInternalMethod(cxt, jsp, jb, found);
+		}
+		break;
+
+
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", jsp->type);
 	}
@@ -2792,6 +2811,176 @@ executeDateTimeMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
 	return executeNextItem(cxt, jsp, &elem, jb, found, hasNext);
 }
 
+/*
+ * Implementation of .upper(), lower() et. al. methods,
+ * that forward their actual implementation to internal functions.
+ */
+static JsonPathExecResult executeStringInternalMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
+												JsonbValue *jb, JsonValueList *found) {
+	Assert(	jsp->type == jpiStrLowerFunc ||
+			jsp->type == jpiStrUpperFunc ||
+			jsp->type == jpiReplaceFunc ||
+			jsp->type == jpiStrLtrimFunc ||
+			jsp->type == jpiStrRtrimFunc ||
+			jsp->type == jpiStrBtrimFunc ||
+			jsp->type == jpiStrInitcapFunc ||
+			jsp->type == jpiStrSplitPartFunc);
+	JsonbValue	jbvbuf;
+	bool		hasNext;
+	JsonPathExecResult res = jperNotFound;
+	JsonPathItem elem;
+	Datum		str; /* Datum representation for the current string value. The first argument to internal functions */
+	char		*tmp = NULL;
+	char		*resStr = NULL;
+
+	if (!(jb = getScalar(jb, jbvString)))
+		RETURN_ERROR(ereport(ERROR,
+							 (errcode(ERRCODE_INVALID_ARGUMENT_FOR_SQL_JSON_DATETIME_FUNCTION),
+							  errmsg("jsonpath item method .%s() can only be applied to a string",
+									 jspOperationName(jsp->type)))));
+
+	tmp = pnstrdup(jb->val.string.val, jb->val.string.len);
+	str = CStringGetTextDatum(tmp);
+
+	/* Internal string functions that accept no arguments */
+	switch (jsp->type)
+	{
+		case jpiStrLtrimFunc:
+		case jpiStrRtrimFunc:
+		case jpiStrBtrimFunc:
+		{
+			char	   *characters_str;
+			int			characters_len;
+			PGFunction	func = NULL;
+
+			switch (jsp->type)
+			{
+				case jpiStrLtrimFunc:
+					func = ltrim1;
+					break;
+				case jpiStrRtrimFunc:
+					func = rtrim1;
+					break;
+				case jpiStrBtrimFunc:
+					func = btrim1;
+					break;
+				default: ;
+			}
+
+			if (jsp->content.arg)
+			{
+				jspGetArg(jsp, &elem);
+				if (elem.type != jpiString)
+					elog(ERROR, "invalid jsonpath item type for .%s() argument", jspOperationName(jsp->type));
+
+				characters_str = jspGetString(&elem, &characters_len);
+				resStr = TextDatumGetCString(DirectFunctionCall2Coll(func,
+					DEFAULT_COLLATION_OID, str,
+					CStringGetTextDatum(characters_str)));
+				break;
+			}
+
+			resStr = TextDatumGetCString(DirectFunctionCall2Coll(func,
+					DEFAULT_COLLATION_OID, str,
+					CStringGetTextDatum(" ")));
+			break;
+		}
+
+		case jpiStrLowerFunc:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(lower, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiStrUpperFunc:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(upper, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiStrInitcapFunc:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(initcap, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiReplaceFunc:
+		{
+			char		*from_str, *to_str;
+			int			from_len, to_len;
+
+			jspGetArg0(jsp, &elem);
+			if (elem.type != jpiString)
+				elog(ERROR, "invalid jsonpath item type for .replace() from");
+
+			from_str = jspGetString(&elem, &from_len);
+
+			jspGetArg1(jsp, &elem);
+			if (elem.type != jpiString)
+				elog(ERROR, "invalid jsonpath item type for .replace() to");
+
+			to_str = jspGetString(&elem, &to_len);
+
+			resStr = TextDatumGetCString(DirectFunctionCall3Coll(replace_text,
+				C_COLLATION_OID,
+				CStringGetTextDatum(tmp),
+				CStringGetTextDatum(from_str),
+				CStringGetTextDatum(to_str)));
+			break;
+		}
+		case jpiStrSplitPartFunc:
+		{
+			char		*from_str;
+			Numeric		n;
+			int			from_len;
+
+			jspGetArg0(jsp, &elem);
+			if (elem.type != jpiString)
+				elog(ERROR, "invalid jsonpath item type for .split_part()");
+
+			from_str = jspGetString(&elem, &from_len);
+
+			jspGetArg1(jsp, &elem);
+			if (elem.type != jpiNumeric)
+				elog(ERROR, "invalid jsonpath item type for .split_part()");
+
+			n = jspGetNumeric(&elem);
+
+			resStr = TextDatumGetCString(DirectFunctionCall3Coll(split_part,
+				C_COLLATION_OID,
+				CStringGetTextDatum(tmp),
+				CStringGetTextDatum(from_str),
+				DirectFunctionCall1(numeric_int8, NumericGetDatum(n))));
+			break;
+		}
+		default:
+			elog(ERROR, "unsupported jsonpath item type: %d", jsp->type);
+	}
+
+	if (resStr)
+		res = jperOk;
+
+	hasNext = jspGetNext(jsp, &elem);
+
+	if (!hasNext && !found)
+		return res;
+
+	jb = hasNext ? &jbvbuf : palloc(sizeof(*jb));
+
+	/* Create the appropriate jb value to return */
+	switch (jsp->type)
+	{
+		/* Cases for functions that return text */
+		case jpiStrLowerFunc:
+		case jpiStrUpperFunc:
+		case jpiReplaceFunc:
+		case jpiStrLtrimFunc:
+		case jpiStrRtrimFunc:
+		case jpiStrBtrimFunc:
+		case jpiStrInitcapFunc:
+		case jpiStrSplitPartFunc:
+			jb->type = jbvString;
+			jb->val.string.val = resStr;
+			jb->val.string.len = strlen(jb->val.string.val);
+		default:
+			;
+			/* cant' happen */
+	}
+
+	return executeNextItem(cxt, jsp, &elem, jb, found, hasNext);
+}
+
 /*
  * Implementation of .keyvalue() method.
  *
diff --git a/src/backend/utils/adt/jsonpath_gram.y b/src/backend/utils/adt/jsonpath_gram.y
index 499745a8fef..cf7a4ff19fd 100644
--- a/src/backend/utils/adt/jsonpath_gram.y
+++ b/src/backend/utils/adt/jsonpath_gram.y
@@ -43,6 +43,9 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 							  JsonPathString *flags,
 							  JsonPathParseItem ** result,
 							  struct Node *escontext);
+static JsonPathParseItem *makeItemReplaceFunc(JsonPathParseItem *arg0, JsonPathParseItem *arg1);
+static JsonPathParseItem *makeItemStrSplitPartFunc(JsonPathParseItem *arg0, JsonPathParseItem *arg1);
+
 
 /*
  * Bison doesn't allocate anything that needs to live across parser calls,
@@ -86,6 +89,8 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 %token	<str>		DATETIME_P
 %token	<str>		BIGINT_P BOOLEAN_P DATE_P DECIMAL_P INTEGER_P NUMBER_P
 %token	<str>		STRINGFUNC_P TIME_P TIME_TZ_P TIMESTAMP_P TIMESTAMP_TZ_P
+%token	<str>		STR_REPLACEFUNC_P STR_LOWER_P STR_UPPER_P STR_LTRIM_P STR_RTRIM_P STR_BTRIM_P
+					STR_INITCAP_P STR_SPLIT_PART_P
 
 %type	<result>	result
 
@@ -94,8 +99,9 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 					index_elem starts_with_initial expr_or_predicate
 					datetime_template opt_datetime_template csv_elem
 					datetime_precision opt_datetime_precision
+					str_method_arg_elem
 
-%type	<elems>		accessor_expr csv_list opt_csv_list
+%type	<elems>		accessor_expr csv_list opt_csv_list str_method_arg_list
 
 %type	<indexs>	index_list
 
@@ -278,6 +284,32 @@ accessor_op:
 		{ $$ = makeItemUnary(jpiTimestamp, $4); }
 	| '.' TIMESTAMP_TZ_P '(' opt_datetime_precision ')'
 		{ $$ = makeItemUnary(jpiTimestampTz, $4); }
+	| '.' STR_REPLACEFUNC_P '(' str_method_arg_list ')'
+		{
+			if (list_length($4) == 2)
+				$$ = makeItemReplaceFunc(linitial($4), lsecond($4));
+			else
+				ereturn(escontext, false,
+						(errcode(ERRCODE_SYNTAX_ERROR),
+						 errmsg("invalid input syntax for type %s", "jsonpath"),
+						 errdetail(".replace() accepts two arguments.")));
+		}
+	| '.' STR_SPLIT_PART_P '(' STRING_P csv_elem ')'
+		{
+			if (list_length($4) == 2)
+				$$ = makeItemStrSplitPartFunc(linitial($4), lsecond($4));
+			else
+				ereturn(escontext, false,
+						(errcode(ERRCODE_SYNTAX_ERROR),
+						 errmsg("invalid input syntax for type %s", "jsonpath"),
+						 errdetail(".split_part() accepts two arguments.")));
+		}
+	| '.' STR_LTRIM_P '(' opt_datetime_template ')'
+		{ $$ = makeItemUnary(jpiStrLtrimFunc, $4); }
+	| '.' STR_RTRIM_P '(' opt_datetime_template ')'
+		{ $$ = makeItemUnary(jpiStrRtrimFunc, $4); }
+	| '.' STR_BTRIM_P '(' opt_datetime_template ')'
+		{ $$ = makeItemUnary(jpiStrBtrimFunc, $4); }
 	;
 
 csv_elem:
@@ -317,6 +349,15 @@ opt_datetime_template:
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
+str_method_arg_elem:
+	STRING_P						{ $$ = makeItemString(&$1); }
+	| INT_P							{ $$ = makeItemNumeric(&$1); }
+	;
+
+str_method_arg_list:
+	str_method_arg_elem							{ $$ = list_make1($1); }
+	| str_method_arg_list ',' str_method_arg_elem	{ $$ = lappend($1, $3); }
+	;
 key:
 	key_name						{ $$ = makeItemKey(&$1); }
 	;
@@ -357,6 +398,9 @@ key_name:
 	| TIME_TZ_P
 	| TIMESTAMP_P
 	| TIMESTAMP_TZ_P
+	| STR_LTRIM_P
+	| STR_RTRIM_P
+	| STR_BTRIM_P
 	;
 
 method:
@@ -373,6 +417,9 @@ method:
 	| INTEGER_P						{ $$ = jpiInteger; }
 	| NUMBER_P						{ $$ = jpiNumber; }
 	| STRINGFUNC_P					{ $$ = jpiStringFunc; }
+	| STR_LOWER_P					{ $$ = jpiStrLowerFunc; }
+	| STR_UPPER_P					{ $$ = jpiStrUpperFunc; }
+	| STR_INITCAP_P					{ $$ = jpiStrInitcapFunc; }
 	;
 %%
 
@@ -472,6 +519,28 @@ makeItemBinary(JsonPathItemType type, JsonPathParseItem *la, JsonPathParseItem *
 	return v;
 }
 
+static JsonPathParseItem *
+makeItemReplaceFunc(JsonPathParseItem *arg0, JsonPathParseItem *arg1)
+{
+	JsonPathParseItem *v = makeItemType(jpiReplaceFunc);
+
+	v->value.method_args.arg0 = arg0;
+	v->value.method_args.arg1 = arg1;
+
+	return v;
+}
+
+static JsonPathParseItem *
+makeItemStrSplitPartFunc(JsonPathParseItem *arg0, JsonPathParseItem *arg1)
+{
+	JsonPathParseItem *v = makeItemType(jpiStrSplitPartFunc);
+
+	v->value.method_args.arg0 = arg0;
+	v->value.method_args.arg1 = arg1;
+
+	return v;
+}
+
 static JsonPathParseItem *
 makeItemUnary(JsonPathItemType type, JsonPathParseItem *a)
 {
diff --git a/src/backend/utils/adt/jsonpath_scan.l b/src/backend/utils/adt/jsonpath_scan.l
index c7aab83eeb4..f20e9e5f1d3 100644
--- a/src/backend/utils/adt/jsonpath_scan.l
+++ b/src/backend/utils/adt/jsonpath_scan.l
@@ -433,6 +433,47 @@ static const JsonPathKeyword keywords[] = {
 	{9, false, TIMESTAMP_P, "timestamp"},
 	{10, false, LIKE_REGEX_P, "like_regex"},
 	{12, false, TIMESTAMP_TZ_P, "timestamp_tz"},
+	{ 2, false,	IS_P,		"is"},
+	{ 2, false,	TO_P,		"to"},
+	{ 3, false,	ABS_P,		"abs"},
+	{ 3, false,	LAX_P,		"lax"},
+	{ 4, false,	DATE_P,		"date"},
+	{ 4, false,	FLAG_P,		"flag"},
+	{ 4, false,	LAST_P,		"last"},
+	{ 4, true,	NULL_P,		"null"},
+	{ 4, false,	SIZE_P,		"size"},
+	{ 4, false,	TIME_P,		"time"},
+	{ 4, true,	TRUE_P,		"true"},
+	{ 4, false,	TYPE_P,		"type"},
+	{ 4, false,	WITH_P,		"with"},
+	{ 5, false, STR_BTRIM_P, "btrim"},
+	{ 5, true,	FALSE_P,	"false"},
+	{ 5, false,	FLOOR_P,	"floor"},
+	{ 5, false, STR_LOWER_P, "lower"},
+	{ 5, false, STR_LTRIM_P, "ltrim"},
+	{ 5, false, STR_RTRIM_P, "rtrim"},
+	{ 5, false, STR_UPPER_P, "upper"},
+	{ 6, false,	BIGINT_P,	"bigint"},
+	{ 6, false,	DOUBLE_P,	"double"},
+	{ 6, false,	EXISTS_P,	"exists"},
+	{ 6, false,	NUMBER_P,	"number"},
+	{ 6, false,	STARTS_P,	"starts"},
+	{ 6, false,	STRICT_P,	"strict"},
+	{ 6, false,	STRINGFUNC_P, "string"},
+	{ 7, false,	BOOLEAN_P,	"boolean"},
+	{ 7, false,	CEILING_P,	"ceiling"},
+	{ 7, false,	DECIMAL_P,	"decimal"},
+	{ 7, false, STR_INITCAP_P, "initcap"},
+	{ 7, false,	INTEGER_P,	"integer"},
+	{ 7, false, STR_REPLACEFUNC_P, "replace"},
+	{ 7, false,	TIME_TZ_P,	"time_tz"},
+	{ 7, false,	UNKNOWN_P,	"unknown"},
+	{ 8, false,	DATETIME_P,	"datetime"},
+	{ 8, false,	KEYVALUE_P,	"keyvalue"},
+	{ 9, false,	TIMESTAMP_P, "timestamp"},
+	{ 10,false, LIKE_REGEX_P, "like_regex"},
+	{ 10,false, STR_SPLIT_PART_P, "split_part"},
+	{ 12,false, TIMESTAMP_TZ_P, "timestamp_tz"},
 };
 
 /*
diff --git a/src/include/utils/jsonpath.h b/src/include/utils/jsonpath.h
index 23a76d233e9..4c60f9d1826 100644
--- a/src/include/utils/jsonpath.h
+++ b/src/include/utils/jsonpath.h
@@ -115,6 +115,14 @@ typedef enum JsonPathItemType
 	jpiTimeTz,					/* .time_tz() item method */
 	jpiTimestamp,				/* .timestamp() item method */
 	jpiTimestampTz,				/* .timestamp_tz() item method */
+	jpiReplaceFunc,				/* .replace() item method */
+	jpiStrLowerFunc,			/* .lower() item method */
+	jpiStrUpperFunc,			/* .upper() item method */
+	jpiStrLtrimFunc,			/* .ltrim() item method */
+	jpiStrRtrimFunc,			/* .rtrim() item method */
+	jpiStrBtrimFunc,			/* .btrim() item method */
+	jpiStrInitcapFunc,			/* .initcap() item method */
+	jpiStrSplitPartFunc,		/* .split_part() item method */
 } JsonPathItemType;
 
 /* XQuery regex mode flags for LIKE_REGEX predicate */
@@ -188,6 +196,12 @@ typedef struct JsonPathItem
 			int32		patternlen;
 			uint32		flags;
 		}			like_regex;
+
+		struct
+		{
+			int32		arg0;
+			int32		arg1;
+		}			method_args;
 	}			content;
 } JsonPathItem;
 
@@ -199,6 +213,8 @@ extern bool jspGetNext(JsonPathItem *v, JsonPathItem *a);
 extern void jspGetArg(JsonPathItem *v, JsonPathItem *a);
 extern void jspGetLeftArg(JsonPathItem *v, JsonPathItem *a);
 extern void jspGetRightArg(JsonPathItem *v, JsonPathItem *a);
+extern void jspGetArg0(JsonPathItem *v, JsonPathItem *a);
+extern void jspGetArg1(JsonPathItem *v, JsonPathItem *a);
 extern Numeric jspGetNumeric(JsonPathItem *v);
 extern bool jspGetBool(JsonPathItem *v);
 extern char *jspGetString(JsonPathItem *v, int32 *len);
@@ -266,6 +282,12 @@ struct JsonPathParseItem
 			uint32		len;
 			char	   *val;	/* could not be not null-terminated */
 		}			string;
+
+		struct
+		{
+			JsonPathParseItem *arg0;
+			JsonPathParseItem *arg1;
+		}			method_args;
 	}			value;
 };
 
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e91a29..2dbaec92129 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -2723,6 +2723,399 @@ select jsonb_path_query('"2023-08-15 12:34:56"', '$.timestamp().string()');
 (1 row)
 
 rollback;
+-- test .ltrim()
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('null', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('null', '$.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.ltrim()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('{}', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('true', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('1234', '$.ltrim().type()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim()');
+  jsonb_path_query_array  
+--------------------------
+ ["maybe  ", "yes", "no"]
+(1 row)
+
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .rtrim()
+select jsonb_path_query('"   hello   "', '$.rtrim(" ")');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.rtrim(" ")');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+-- test .btrim()
+select jsonb_path_query('"   hello   "', '$.btrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.btrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.btrim()');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.btrim()');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+-- test .lower()
+select jsonb_path_query('null', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('null', '$.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.lower()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('{}', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.lower()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.lower()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('true', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('1234', '$.lower().type()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower()');
+ jsonb_path_query_array 
+------------------------
+ ["maybe", "yes", "no"]
+(1 row)
+
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .upper()
+select jsonb_path_query('null', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('null', '$.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.upper()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('{}', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.upper()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.upper()');
+ jsonb_path_query 
+------------------
+ "1.23AAA"
+(1 row)
+
+select jsonb_path_query('1234', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('true', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('1234', '$.upper().type()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper()');
+ jsonb_path_query_array 
+------------------------
+ ["MAYBE", "YES", "NO"]
+(1 row)
+
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .initcap()
+select jsonb_path_query('null', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('null', '$.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.initcap()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('{}', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('true', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('1234', '$.initcap().type()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('["maybe yes", "probably no"]', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "Maybe Yes"
+ "Probably No"
+(2 rows)
+
+-- Test .replace()
+select jsonb_path_query('null', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('null', '$.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('["x", "y", "z"]', '$.replace("x", "bye")');
+ jsonb_path_query 
+------------------
+ "bye"
+ "y"
+ "z"
+(3 rows)
+
+select jsonb_path_query('{}', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('"hello world"', '$.replace("hello","bye")');
+ jsonb_path_query 
+------------------
+ "bye world"
+(1 row)
+
+select jsonb_path_query('"hello world"', '$.replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
+-- Test .split_part()
+select jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)');
+ jsonb_path_query 
+------------------
+ "def"
+(1 row)
+
+-- Test string methods play nicely together
+select jsonb_path_query('"hello world"', '$.replace("hello","bye").upper()');
+ jsonb_path_query 
+------------------
+ "BYE WORLD"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye")');
+ jsonb_path_query 
+------------------
+ "bye world"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.upper().lower().upper().replace("HELLO", "BYE")');
+ jsonb_path_query 
+------------------
+ "BYE WORLD"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
+select jsonb_path_query('"   hElLo WorlD "', '$.btrim().lower().upper().lower().replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
 -- Test .time()
 select jsonb_path_query('null', '$.time()');
 ERROR:  jsonpath item method .time() can only be applied to a string
diff --git a/src/test/regress/expected/jsonpath.out b/src/test/regress/expected/jsonpath.out
index fd9bd755f52..1b122e877d5 100644
--- a/src/test/regress/expected/jsonpath.out
+++ b/src/test/regress/expected/jsonpath.out
@@ -435,6 +435,78 @@ select '$.string()'::jsonpath;
  $.string()
 (1 row)
 
+select '$.replace("hello","bye")'::jsonpath;
+         jsonpath         
+--------------------------
+ $.replace("hello","bye")
+(1 row)
+
+select '$.lower()'::jsonpath;
+ jsonpath  
+-----------
+ $.lower()
+(1 row)
+
+select '$.upper()'::jsonpath;
+ jsonpath  
+-----------
+ $.upper()
+(1 row)
+
+select '$.lower().upper().lower().replace("hello","bye")'::jsonpath;
+                     jsonpath                     
+--------------------------------------------------
+ $.lower().upper().lower().replace("hello","bye")
+(1 row)
+
+select '$.ltrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.ltrim()
+(1 row)
+
+select '$.ltrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.ltrim("xyz")
+(1 row)
+
+select '$.rtrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.rtrim()
+(1 row)
+
+select '$.rtrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.rtrim("xyz")
+(1 row)
+
+select '$.btrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.btrim()
+(1 row)
+
+select '$.btrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.btrim("xyz")
+(1 row)
+
+select '$.initcap()'::jsonpath;
+  jsonpath   
+-------------
+ $.initcap()
+(1 row)
+
+select '$.split_part("~@~", 2)'::jsonpath;
+       jsonpath        
+-----------------------
+ $.split_part("~@~",2)
+(1 row)
+
 select '$.time()'::jsonpath;
  jsonpath 
 ----------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a5269..e229e0a0d04 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -623,6 +623,114 @@ select jsonb_path_query('"2023-08-15 12:34:56 +5:30"', '$.timestamp_tz().string(
 select jsonb_path_query('"2023-08-15 12:34:56"', '$.timestamp().string()');
 rollback;
 
+-- test .ltrim()
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+select jsonb_path_query('"   hello   "', '$.ltrim()');
+select jsonb_path_query('"   hello   "', '$.ltrim()');
+select jsonb_path_query('null', '$.ltrim()');
+select jsonb_path_query('null', '$.ltrim()', silent => true);
+select jsonb_path_query('[]', '$.ltrim()');
+select jsonb_path_query('[]', 'strict $.ltrim()');
+select jsonb_path_query('{}', '$.ltrim()');
+select jsonb_path_query('[]', 'strict $.ltrim()', silent => true);
+select jsonb_path_query('{}', '$.ltrim()', silent => true);
+select jsonb_path_query('1.23', '$.ltrim()');
+select jsonb_path_query('"1.23"', '$.ltrim()');
+select jsonb_path_query('"1.23aaa"', '$.ltrim()');
+select jsonb_path_query('1234', '$.ltrim()');
+select jsonb_path_query('true', '$.ltrim()');
+select jsonb_path_query('1234', '$.ltrim().type()');
+select jsonb_path_query('[2, true]', '$.ltrim()');
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim()');
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim().type()');
+
+-- test .rtrim()
+select jsonb_path_query('"   hello   "', '$.rtrim(" ")');
+select jsonb_path_query('"   hello   "', '$.rtrim(" ")');
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+
+-- test .btrim()
+select jsonb_path_query('"   hello   "', '$.btrim(" ")');
+select jsonb_path_query('"   hello   "', '$.btrim(" ")');
+select jsonb_path_query('"   hello   "', '$.btrim()');
+select jsonb_path_query('"   hello   "', '$.btrim()');
+
+-- test .lower()
+select jsonb_path_query('null', '$.lower()');
+select jsonb_path_query('null', '$.lower()', silent => true);
+select jsonb_path_query('[]', '$.lower()');
+select jsonb_path_query('[]', 'strict $.lower()');
+select jsonb_path_query('{}', '$.lower()');
+select jsonb_path_query('[]', 'strict $.lower()', silent => true);
+select jsonb_path_query('{}', '$.lower()', silent => true);
+select jsonb_path_query('1.23', '$.lower()');
+select jsonb_path_query('"1.23"', '$.lower()');
+select jsonb_path_query('"1.23aaa"', '$.lower()');
+select jsonb_path_query('1234', '$.lower()');
+select jsonb_path_query('true', '$.lower()');
+select jsonb_path_query('1234', '$.lower().type()');
+select jsonb_path_query('[2, true]', '$.lower()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower().type()');
+
+-- test .upper()
+select jsonb_path_query('null', '$.upper()');
+select jsonb_path_query('null', '$.upper()', silent => true);
+select jsonb_path_query('[]', '$.upper()');
+select jsonb_path_query('[]', 'strict $.upper()');
+select jsonb_path_query('{}', '$.upper()');
+select jsonb_path_query('[]', 'strict $.upper()', silent => true);
+select jsonb_path_query('{}', '$.upper()', silent => true);
+select jsonb_path_query('1.23', '$.upper()');
+select jsonb_path_query('"1.23"', '$.upper()');
+select jsonb_path_query('"1.23aaa"', '$.upper()');
+select jsonb_path_query('1234', '$.upper()');
+select jsonb_path_query('true', '$.upper()');
+select jsonb_path_query('1234', '$.upper().type()');
+select jsonb_path_query('[2, true]', '$.upper()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper().type()');
+
+-- test .initcap()
+select jsonb_path_query('null', '$.initcap()');
+select jsonb_path_query('null', '$.initcap()', silent => true);
+select jsonb_path_query('[]', '$.initcap()');
+select jsonb_path_query('[]', 'strict $.initcap()');
+select jsonb_path_query('{}', '$.initcap()');
+select jsonb_path_query('[]', 'strict $.initcap()', silent => true);
+select jsonb_path_query('{}', '$.initcap()', silent => true);
+select jsonb_path_query('1.23', '$.initcap()');
+select jsonb_path_query('"1.23"', '$.initcap()');
+select jsonb_path_query('"1.23aaa"', '$.initcap()');
+select jsonb_path_query('1234', '$.initcap()');
+select jsonb_path_query('true', '$.initcap()');
+select jsonb_path_query('1234', '$.initcap().type()');
+select jsonb_path_query('[2, true]', '$.initcap()');
+select jsonb_path_query('["maybe yes", "probably no"]', '$.initcap()');
+
+-- Test .replace()
+select jsonb_path_query('null', '$.replace("x", "bye")');
+select jsonb_path_query('null', '$.replace("x", "bye")', silent => true);
+select jsonb_path_query('["x", "y", "z"]', '$.replace("x", "bye")');
+select jsonb_path_query('{}', '$.replace("x", "bye")');
+select jsonb_path_query('[]', 'strict $.replace("x", "bye")', silent => true);
+select jsonb_path_query('{}', '$.replace("x", "bye")', silent => true);
+select jsonb_path_query('1.23', '$.replace("x", "bye")');
+select jsonb_path_query('"hello world"', '$.replace("hello","bye")');
+select jsonb_path_query('"hello world"', '$.replace("hello","bye") starts with "bye"');
+
+-- Test .split_part()
+select jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)');
+
+-- Test string methods play nicely together
+select jsonb_path_query('"hello world"', '$.replace("hello","bye").upper()');
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye")');
+select jsonb_path_query('"hElLo WorlD"', '$.upper().lower().upper().replace("HELLO", "BYE")');
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye") starts with "bye"');
+select jsonb_path_query('"   hElLo WorlD "', '$.btrim().lower().upper().lower().replace("hello","bye") starts with "bye"');
+
 -- Test .time()
 select jsonb_path_query('null', '$.time()');
 select jsonb_path_query('true', '$.time()');
diff --git a/src/test/regress/sql/jsonpath.sql b/src/test/regress/sql/jsonpath.sql
index 61a5270d4e8..8752ffcf08c 100644
--- a/src/test/regress/sql/jsonpath.sql
+++ b/src/test/regress/sql/jsonpath.sql
@@ -78,6 +78,19 @@ select '$.boolean()'::jsonpath;
 select '$.date()'::jsonpath;
 select '$.decimal(4,2)'::jsonpath;
 select '$.string()'::jsonpath;
+select '$.replace("hello","bye")'::jsonpath;
+select '$.lower()'::jsonpath;
+select '$.upper()'::jsonpath;
+select '$.lower().upper().lower().replace("hello","bye")'::jsonpath;
+select '$.ltrim()'::jsonpath;
+select '$.ltrim("xyz")'::jsonpath;
+select '$.rtrim()'::jsonpath;
+select '$.rtrim("xyz")'::jsonpath;
+select '$.btrim()'::jsonpath;
+select '$.btrim("xyz")'::jsonpath;
+select '$.initcap()'::jsonpath;
+select '$.split_part("~@~", 2)'::jsonpath;
+
 select '$.time()'::jsonpath;
 select '$.time(6)'::jsonpath;
 select '$.time_tz()'::jsonpath;
-- 
2.49.0

From 6a4705fd7cd79de9ad49e679fe15e5b2ca19fe10 Mon Sep 17 00:00:00 2001
From: Florents Tselai <florents.tselai@gmail.com>
Date: Sat, 24 May 2025 17:55:08 -0400
Subject: [PATCH v4] Add additional jsonpath string methods

Add the following jsonpath methods:

*   l/r/btrim()
*   lower(), upper()
*   initcap()
*   replace()
*   split_part()

Each simply dispatches to the standard string processing functions.
These depend on the locale, but since it's set at `initdb`, they can be
considered immutable and therefore allowed in any jsonpath expression.
---
 doc/src/sgml/func.sgml                       | 171 ++++++++
 src/backend/utils/adt/jsonpath.c             | 176 ++++++++-
 src/backend/utils/adt/jsonpath_exec.c        | 189 +++++++++
 src/backend/utils/adt/jsonpath_gram.y        |  71 +++-
 src/backend/utils/adt/jsonpath_scan.l        |  41 ++
 src/include/utils/jsonpath.h                 |  22 ++
 src/test/regress/expected/jsonb_jsonpath.out | 393 +++++++++++++++++++
 src/test/regress/expected/jsonpath.out       |  72 ++++
 src/test/regress/sql/jsonb_jsonpath.sql      | 108 +++++
 src/test/regress/sql/jsonpath.sql            |  13 +
 10 files changed, 1252 insertions(+), 4 deletions(-)

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index c67688cbf5f..25d0d920dbf 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -18627,6 +18627,177 @@ ERROR:  jsonpath member accessor can only be applied to an object
         <returnvalue>[{"id": 0, "key": "x", "value": "20"}, {"id": 0, "key": "y", "value": 32}]</returnvalue>
        </para></entry>
       </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>lower()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String converted to all lower case according to the rules of the database's locale.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"TOM"', '$.lower()')</literal>
+        <returnvalue>"tom"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>upper()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String converted to all upper case according to the rules of the database's locale.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"tom"', '$.upper()')</literal>
+        <returnvalue>"TOM"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>initcap()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the first letter of each word converted to upper case
+        according to the rules of the database's locale. Words are sequences
+        of alphanumeric characters separated by non-alphanumeric characters.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"hi THOMAS"', '$.initcap()')</literal>
+        <returnvalue>"Hi Thomas"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>replace(<replaceable>from</replaceable>, <replaceable>to</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with all occurrences of substring from replaced with substring to.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"abcdefabcdef"', '$.replace("cd", "XX")')</literal>
+        <returnvalue>"abXXefabXXef"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>split_part(<replaceable>delimiter</replaceable>, <replaceable>n</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String split at occurrences of <replaceable>delimiter</replaceable>
+        and returns the <replaceable>n</replaceable>'th field (counting from
+        one) or, when <replaceable>n</replaceable> is negative, returns the
+        |<replaceable>n</replaceable>|'th-from-last field.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)')</literal>
+        <returnvalue>"def"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"abc,def,ghi,jkl"', '$.split_part(",", 2)')</literal>
+        <returnvalue>"ghi"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>ltrim()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with spaces removed from the start of <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal> jsonb_path_query('"  hello"', '$.ltrim()')</literal>
+        <returnvalue>"hello"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>ltrim(<replaceable>characters</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the longest string containing only characters in
+        <replaceable>characters</replaceable> removed from the start of
+        <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"zzzytest"', '$.ltrim("xyz")')</literal>
+        <returnvalue>"test"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>rtrim()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with spaces removed from the end of <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"hello  "', '$.rtrim()')</literal>
+        <returnvalue>"hello"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>rtrim(<replaceable>characters</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the longest string containing only characters in
+        <replaceable>characters</replaceable> removed from the end of
+        <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"testxxzx"', '$.rtrim("xyz")')</literal>
+        <returnvalue>"test"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>btrim()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with spaces removed from the start and end of
+        <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"  hello  "', '$.btrim()')</literal>
+        <returnvalue>"hello"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>btrim(<replaceable>characters</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the longest string containing only characters in
+        <replaceable>characters</replaceable> removed from the start and end
+        of <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"xyxtrimyyx"', '$.btrim("xyz")')</literal>
+        <returnvalue>"trim"</returnvalue>
+       </para></entry>
+      </row>
+
      </tbody>
     </tgroup>
    </table>
diff --git a/src/backend/utils/adt/jsonpath.c b/src/backend/utils/adt/jsonpath.c
index 762f7e8a09d..646c7b460a3 100644
--- a/src/backend/utils/adt/jsonpath.c
+++ b/src/backend/utils/adt/jsonpath.c
@@ -326,6 +326,38 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 				*(int32 *) (buf->data + right) = chld - pos;
 			}
 			break;
+		case jpiReplaceFunc:
+		case jpiStrSplitPartFunc:
+		{
+			{
+				/*
+				 * First, reserve place for left/right arg's positions, then
+				 * record both args and sets actual position in reserved
+				 * places.
+				 */
+				int32		arg0 = reserveSpaceForItemPointer(buf);
+				int32		arg1 = reserveSpaceForItemPointer(buf);
+
+				if (!item->value.method_args.arg0)
+					chld = pos;
+				else if (!flattenJsonPathParseItem(buf, &chld, escontext,
+												   item->value.method_args.arg0,
+												   nestingLevel + argNestingLevel,
+												   insideArraySubscript))
+					return false;
+				*(int32 *) (buf->data + arg0) = chld - pos;
+
+				if (!item->value.method_args.arg1)
+					chld = pos;
+				else if (!flattenJsonPathParseItem(buf, &chld, escontext,
+												   item->value.method_args.arg1,
+												   nestingLevel + argNestingLevel,
+												   insideArraySubscript))
+					return false;
+				*(int32 *) (buf->data + arg1) = chld - pos;
+			}
+		}
+		break;
 		case jpiLikeRegex:
 			{
 				int32		offs;
@@ -362,6 +394,9 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 		case jpiTimeTz:
 		case jpiTimestamp:
 		case jpiTimestampTz:
+		case jpiStrLtrimFunc:
+		case jpiStrRtrimFunc:
+		case jpiStrBtrimFunc:
 			{
 				int32		arg = reserveSpaceForItemPointer(buf);
 
@@ -457,6 +492,9 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 		case jpiInteger:
 		case jpiNumber:
 		case jpiStringFunc:
+		case jpiStrLowerFunc:
+		case jpiStrUpperFunc:
+		case jpiStrInitcapFunc:
 			break;
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", item->type);
@@ -831,6 +869,72 @@ printJsonPathItem(StringInfo buf, JsonPathItem *v, bool inKey,
 			}
 			appendStringInfoChar(buf, ')');
 			break;
+		case jpiReplaceFunc:
+			appendStringInfoString(buf, ".replace(");
+			if (v->content.method_args.arg0)
+			{
+				jspGetArg0(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			if (v->content.method_args.arg1)
+			{
+				appendStringInfoChar(buf, ',');
+				jspGetArg1(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrSplitPartFunc:
+			appendStringInfoString(buf, ".split_part(");
+			if (v->content.method_args.arg0)
+			{
+				jspGetArg0(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			if (v->content.method_args.arg1)
+			{
+				appendStringInfoChar(buf, ',');
+				jspGetArg1(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrLowerFunc:
+			appendStringInfoString(buf, ".lower()");
+			break;
+		case jpiStrUpperFunc:
+			appendStringInfoString(buf, ".upper()");
+			break;
+		case jpiStrInitcapFunc:
+			appendStringInfoString(buf, ".initcap()");
+			break;
+		case jpiStrLtrimFunc:
+			appendStringInfoString(buf, ".ltrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrRtrimFunc:
+			appendStringInfoString(buf, ".rtrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrBtrimFunc:
+			appendStringInfoString(buf, ".btrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", v->type);
 	}
@@ -906,6 +1010,12 @@ jspOperationName(JsonPathItemType type)
 			return "number";
 		case jpiStringFunc:
 			return "string";
+		case jpiReplaceFunc:
+			return "replace";
+		case jpiStrLowerFunc:
+			return "lower";
+		case jpiStrUpperFunc:
+			return "upper";
 		case jpiTime:
 			return "time";
 		case jpiTimeTz:
@@ -914,6 +1024,16 @@ jspOperationName(JsonPathItemType type)
 			return "timestamp";
 		case jpiTimestampTz:
 			return "timestamp_tz";
+		case jpiStrLtrimFunc:
+			return "ltrim";
+		case jpiStrRtrimFunc:
+			return "rtrim";
+		case jpiStrBtrimFunc:
+			return "btrim";
+		case jpiStrInitcapFunc:
+			return "initcap";
+		case jpiStrSplitPartFunc:
+			return "split_part";
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", type);
 			return NULL;
@@ -1016,6 +1136,9 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 		case jpiInteger:
 		case jpiNumber:
 		case jpiStringFunc:
+		case jpiStrLowerFunc:
+		case jpiStrUpperFunc:
+		case jpiStrInitcapFunc:
 			break;
 		case jpiString:
 		case jpiKey:
@@ -1044,6 +1167,11 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 			read_int32(v->content.args.left, base, pos);
 			read_int32(v->content.args.right, base, pos);
 			break;
+		case jpiReplaceFunc:
+		case jpiStrSplitPartFunc:
+			read_int32(v->content.method_args.arg0, base, pos);
+			read_int32(v->content.method_args.arg1, base, pos);
+		break;
 		case jpiNot:
 		case jpiIsUnknown:
 		case jpiExists:
@@ -1055,6 +1183,9 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 		case jpiTimeTz:
 		case jpiTimestamp:
 		case jpiTimestampTz:
+		case jpiStrLtrimFunc:
+		case jpiStrRtrimFunc:
+		case jpiStrBtrimFunc:
 			read_int32(v->content.arg, base, pos);
 			break;
 		case jpiIndexArray:
@@ -1090,7 +1221,10 @@ jspGetArg(JsonPathItem *v, JsonPathItem *a)
 		   v->type == jpiTime ||
 		   v->type == jpiTimeTz ||
 		   v->type == jpiTimestamp ||
-		   v->type == jpiTimestampTz);
+		   v->type == jpiTimestampTz ||
+		   v->type == jpiStrLtrimFunc ||
+		   v->type == jpiStrRtrimFunc ||
+		   v->type == jpiStrBtrimFunc);
 
 	jspInitByBuffer(a, v->base, v->content.arg);
 }
@@ -1149,10 +1283,18 @@ jspGetNext(JsonPathItem *v, JsonPathItem *a)
 			   v->type == jpiInteger ||
 			   v->type == jpiNumber ||
 			   v->type == jpiStringFunc ||
+			   v->type == jpiReplaceFunc ||
+			   v->type == jpiStrLowerFunc ||
+			   v->type == jpiStrUpperFunc ||
 			   v->type == jpiTime ||
 			   v->type == jpiTimeTz ||
 			   v->type == jpiTimestamp ||
-			   v->type == jpiTimestampTz);
+			   v->type == jpiTimestampTz ||
+			   v->type == jpiStrLtrimFunc ||
+			   v->type == jpiStrRtrimFunc ||
+			   v->type == jpiStrBtrimFunc ||
+			   v->type == jpiStrInitcapFunc ||
+			   v->type == jpiStrSplitPartFunc);
 
 		if (a)
 			jspInitByBuffer(a, v->base, v->nextPos);
@@ -1184,6 +1326,24 @@ jspGetLeftArg(JsonPathItem *v, JsonPathItem *a)
 	jspInitByBuffer(a, v->base, v->content.args.left);
 }
 
+void
+jspGetArg0(JsonPathItem *v, JsonPathItem *a)
+{
+	Assert(v->type == jpiReplaceFunc ||
+			v->type == jpiStrSplitPartFunc);
+
+	jspInitByBuffer(a, v->base, v->content.method_args.arg0);
+}
+
+void
+jspGetArg1(JsonPathItem *v, JsonPathItem *a)
+{
+	Assert(v->type == jpiReplaceFunc ||
+			v->type == jpiStrSplitPartFunc);
+
+	jspInitByBuffer(a, v->base, v->content.method_args.arg1);
+}
+
 void
 jspGetRightArg(JsonPathItem *v, JsonPathItem *a)
 {
@@ -1206,6 +1366,7 @@ jspGetRightArg(JsonPathItem *v, JsonPathItem *a)
 	jspInitByBuffer(a, v->base, v->content.args.right);
 }
 
+
 bool
 jspGetBool(JsonPathItem *v)
 {
@@ -1227,7 +1388,8 @@ jspGetString(JsonPathItem *v, int32 *len)
 {
 	Assert(v->type == jpiKey ||
 		   v->type == jpiString ||
-		   v->type == jpiVariable);
+		   v->type == jpiVariable ||
+		   v->type == jpiStringFunc);
 
 	if (len)
 		*len = v->content.value.datalen;
@@ -1501,6 +1663,14 @@ jspIsMutableWalker(JsonPathItem *jpi, struct JsonPathMutableContext *cxt)
 			case jpiInteger:
 			case jpiNumber:
 			case jpiStringFunc:
+			case jpiReplaceFunc:
+			case jpiStrLowerFunc:
+			case jpiStrUpperFunc:
+			case jpiStrLtrimFunc:
+			case jpiStrRtrimFunc:
+			case jpiStrBtrimFunc:
+			case jpiStrInitcapFunc:
+			case jpiStrSplitPartFunc:
 				status = jpdsNonDateTime;
 				break;
 
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index dbab24737ef..51239121f18 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -301,6 +301,8 @@ static JsonPathExecResult executeNumericItemMethod(JsonPathExecContext *cxt,
 												   JsonValueList *found);
 static JsonPathExecResult executeDateTimeMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
 												JsonbValue *jb, JsonValueList *found);
+static JsonPathExecResult executeStringInternalMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
+												JsonbValue *jb, JsonValueList *found);
 static JsonPathExecResult executeKeyValueMethod(JsonPathExecContext *cxt,
 												JsonPathItem *jsp, JsonbValue *jb, JsonValueList *found);
 static JsonPathExecResult appendBoolResult(JsonPathExecContext *cxt,
@@ -1659,6 +1661,23 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
 			}
 			break;
 
+		case jpiStrLtrimFunc:
+		case jpiStrLowerFunc:
+		case jpiStrUpperFunc:
+		case jpiReplaceFunc:
+		case jpiStrRtrimFunc:
+		case jpiStrBtrimFunc:
+		case jpiStrInitcapFunc:
+		case jpiStrSplitPartFunc:
+		{
+			if (unwrap && JsonbType(jb) == jbvArray)
+				return executeItemUnwrapTargetArray(cxt, jsp, jb, found, false);
+
+			return executeStringInternalMethod(cxt, jsp, jb, found);
+		}
+		break;
+
+
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", jsp->type);
 	}
@@ -2792,6 +2811,176 @@ executeDateTimeMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
 	return executeNextItem(cxt, jsp, &elem, jb, found, hasNext);
 }
 
+/*
+ * Implementation of .upper(), lower() et. al. methods,
+ * that forward their actual implementation to internal functions.
+ */
+static JsonPathExecResult executeStringInternalMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
+												JsonbValue *jb, JsonValueList *found) {
+	Assert(	jsp->type == jpiStrLowerFunc ||
+			jsp->type == jpiStrUpperFunc ||
+			jsp->type == jpiReplaceFunc ||
+			jsp->type == jpiStrLtrimFunc ||
+			jsp->type == jpiStrRtrimFunc ||
+			jsp->type == jpiStrBtrimFunc ||
+			jsp->type == jpiStrInitcapFunc ||
+			jsp->type == jpiStrSplitPartFunc);
+	JsonbValue	jbvbuf;
+	bool		hasNext;
+	JsonPathExecResult res = jperNotFound;
+	JsonPathItem elem;
+	Datum		str; /* Datum representation for the current string value. The first argument to internal functions */
+	char		*tmp = NULL;
+	char		*resStr = NULL;
+
+	if (!(jb = getScalar(jb, jbvString)))
+		RETURN_ERROR(ereport(ERROR,
+							 (errcode(ERRCODE_INVALID_ARGUMENT_FOR_SQL_JSON_DATETIME_FUNCTION),
+							  errmsg("jsonpath item method .%s() can only be applied to a string",
+									 jspOperationName(jsp->type)))));
+
+	tmp = pnstrdup(jb->val.string.val, jb->val.string.len);
+	str = CStringGetTextDatum(tmp);
+
+	/* Internal string functions that accept no arguments */
+	switch (jsp->type)
+	{
+		case jpiStrLtrimFunc:
+		case jpiStrRtrimFunc:
+		case jpiStrBtrimFunc:
+		{
+			char	   *characters_str;
+			int			characters_len;
+			PGFunction	func = NULL;
+
+			switch (jsp->type)
+			{
+				case jpiStrLtrimFunc:
+					func = ltrim1;
+					break;
+				case jpiStrRtrimFunc:
+					func = rtrim1;
+					break;
+				case jpiStrBtrimFunc:
+					func = btrim1;
+					break;
+				default: ;
+			}
+
+			if (jsp->content.arg)
+			{
+				jspGetArg(jsp, &elem);
+				if (elem.type != jpiString)
+					elog(ERROR, "invalid jsonpath item type for .%s() argument", jspOperationName(jsp->type));
+
+				characters_str = jspGetString(&elem, &characters_len);
+				resStr = TextDatumGetCString(DirectFunctionCall2Coll(func,
+					DEFAULT_COLLATION_OID, str,
+					CStringGetTextDatum(characters_str)));
+				break;
+			}
+
+			resStr = TextDatumGetCString(DirectFunctionCall2Coll(func,
+					DEFAULT_COLLATION_OID, str,
+					CStringGetTextDatum(" ")));
+			break;
+		}
+
+		case jpiStrLowerFunc:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(lower, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiStrUpperFunc:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(upper, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiStrInitcapFunc:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(initcap, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiReplaceFunc:
+		{
+			char		*from_str, *to_str;
+			int			from_len, to_len;
+
+			jspGetArg0(jsp, &elem);
+			if (elem.type != jpiString)
+				elog(ERROR, "invalid jsonpath item type for .replace() from");
+
+			from_str = jspGetString(&elem, &from_len);
+
+			jspGetArg1(jsp, &elem);
+			if (elem.type != jpiString)
+				elog(ERROR, "invalid jsonpath item type for .replace() to");
+
+			to_str = jspGetString(&elem, &to_len);
+
+			resStr = TextDatumGetCString(DirectFunctionCall3Coll(replace_text,
+				C_COLLATION_OID,
+				CStringGetTextDatum(tmp),
+				CStringGetTextDatum(from_str),
+				CStringGetTextDatum(to_str)));
+			break;
+		}
+		case jpiStrSplitPartFunc:
+		{
+			char		*from_str;
+			Numeric		n;
+			int			from_len;
+
+			jspGetArg0(jsp, &elem);
+			if (elem.type != jpiString)
+				elog(ERROR, "invalid jsonpath item type for .split_part()");
+
+			from_str = jspGetString(&elem, &from_len);
+
+			jspGetArg1(jsp, &elem);
+			if (elem.type != jpiNumeric)
+				elog(ERROR, "invalid jsonpath item type for .split_part()");
+
+			n = jspGetNumeric(&elem);
+
+			resStr = TextDatumGetCString(DirectFunctionCall3Coll(split_part,
+				C_COLLATION_OID,
+				CStringGetTextDatum(tmp),
+				CStringGetTextDatum(from_str),
+				DirectFunctionCall1(numeric_int8, NumericGetDatum(n))));
+			break;
+		}
+		default:
+			elog(ERROR, "unsupported jsonpath item type: %d", jsp->type);
+	}
+
+	if (resStr)
+		res = jperOk;
+
+	hasNext = jspGetNext(jsp, &elem);
+
+	if (!hasNext && !found)
+		return res;
+
+	jb = hasNext ? &jbvbuf : palloc(sizeof(*jb));
+
+	/* Create the appropriate jb value to return */
+	switch (jsp->type)
+	{
+		/* Cases for functions that return text */
+		case jpiStrLowerFunc:
+		case jpiStrUpperFunc:
+		case jpiReplaceFunc:
+		case jpiStrLtrimFunc:
+		case jpiStrRtrimFunc:
+		case jpiStrBtrimFunc:
+		case jpiStrInitcapFunc:
+		case jpiStrSplitPartFunc:
+			jb->type = jbvString;
+			jb->val.string.val = resStr;
+			jb->val.string.len = strlen(jb->val.string.val);
+		default:
+			;
+			/* cant' happen */
+	}
+
+	return executeNextItem(cxt, jsp, &elem, jb, found, hasNext);
+}
+
 /*
  * Implementation of .keyvalue() method.
  *
diff --git a/src/backend/utils/adt/jsonpath_gram.y b/src/backend/utils/adt/jsonpath_gram.y
index 499745a8fef..c998c40cfbd 100644
--- a/src/backend/utils/adt/jsonpath_gram.y
+++ b/src/backend/utils/adt/jsonpath_gram.y
@@ -43,6 +43,9 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 							  JsonPathString *flags,
 							  JsonPathParseItem ** result,
 							  struct Node *escontext);
+static JsonPathParseItem *makeItemReplaceFunc(JsonPathParseItem *arg0, JsonPathParseItem *arg1);
+static JsonPathParseItem *makeItemStrSplitPartFunc(JsonPathParseItem *arg0, JsonPathParseItem *arg1);
+
 
 /*
  * Bison doesn't allocate anything that needs to live across parser calls,
@@ -86,6 +89,8 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 %token	<str>		DATETIME_P
 %token	<str>		BIGINT_P BOOLEAN_P DATE_P DECIMAL_P INTEGER_P NUMBER_P
 %token	<str>		STRINGFUNC_P TIME_P TIME_TZ_P TIMESTAMP_P TIMESTAMP_TZ_P
+%token	<str>		STR_REPLACEFUNC_P STR_LOWER_P STR_UPPER_P STR_LTRIM_P STR_RTRIM_P STR_BTRIM_P
+					STR_INITCAP_P STR_SPLIT_PART_P
 
 %type	<result>	result
 
@@ -94,8 +99,9 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 					index_elem starts_with_initial expr_or_predicate
 					datetime_template opt_datetime_template csv_elem
 					datetime_precision opt_datetime_precision
+					str_method_arg_elem
 
-%type	<elems>		accessor_expr csv_list opt_csv_list
+%type	<elems>		accessor_expr csv_list opt_csv_list str_method_arg_list
 
 %type	<indexs>	index_list
 
@@ -278,6 +284,32 @@ accessor_op:
 		{ $$ = makeItemUnary(jpiTimestamp, $4); }
 	| '.' TIMESTAMP_TZ_P '(' opt_datetime_precision ')'
 		{ $$ = makeItemUnary(jpiTimestampTz, $4); }
+	| '.' STR_REPLACEFUNC_P '(' str_method_arg_list ')'
+		{
+			if (list_length($4) == 2)
+				$$ = makeItemReplaceFunc(linitial($4), lsecond($4));
+			else
+				ereturn(escontext, false,
+						(errcode(ERRCODE_SYNTAX_ERROR),
+						 errmsg("invalid input syntax for type %s", "jsonpath"),
+						 errdetail(".replace() accepts two arguments.")));
+		}
+	| '.' STR_SPLIT_PART_P '(' str_method_arg_list ')'
+		{
+			if (list_length($4) == 2)
+				$$ = makeItemStrSplitPartFunc(linitial($4), lsecond($4));
+			else
+				ereturn(escontext, false,
+						(errcode(ERRCODE_SYNTAX_ERROR),
+						 errmsg("invalid input syntax for type %s", "jsonpath"),
+						 errdetail(".split_part() accepts two arguments.")));
+		}
+	| '.' STR_LTRIM_P '(' opt_datetime_template ')'
+		{ $$ = makeItemUnary(jpiStrLtrimFunc, $4); }
+	| '.' STR_RTRIM_P '(' opt_datetime_template ')'
+		{ $$ = makeItemUnary(jpiStrRtrimFunc, $4); }
+	| '.' STR_BTRIM_P '(' opt_datetime_template ')'
+		{ $$ = makeItemUnary(jpiStrBtrimFunc, $4); }
 	;
 
 csv_elem:
@@ -317,6 +349,15 @@ opt_datetime_template:
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
+str_method_arg_elem:
+	STRING_P						{ $$ = makeItemString(&$1); }
+	| INT_P							{ $$ = makeItemNumeric(&$1); }
+	;
+
+str_method_arg_list:
+	str_method_arg_elem							{ $$ = list_make1($1); }
+	| str_method_arg_list ',' str_method_arg_elem	{ $$ = lappend($1, $3); }
+	;
 key:
 	key_name						{ $$ = makeItemKey(&$1); }
 	;
@@ -357,6 +398,9 @@ key_name:
 	| TIME_TZ_P
 	| TIMESTAMP_P
 	| TIMESTAMP_TZ_P
+	| STR_LTRIM_P
+	| STR_RTRIM_P
+	| STR_BTRIM_P
 	;
 
 method:
@@ -373,6 +417,9 @@ method:
 	| INTEGER_P						{ $$ = jpiInteger; }
 	| NUMBER_P						{ $$ = jpiNumber; }
 	| STRINGFUNC_P					{ $$ = jpiStringFunc; }
+	| STR_LOWER_P					{ $$ = jpiStrLowerFunc; }
+	| STR_UPPER_P					{ $$ = jpiStrUpperFunc; }
+	| STR_INITCAP_P					{ $$ = jpiStrInitcapFunc; }
 	;
 %%
 
@@ -472,6 +519,28 @@ makeItemBinary(JsonPathItemType type, JsonPathParseItem *la, JsonPathParseItem *
 	return v;
 }
 
+static JsonPathParseItem *
+makeItemReplaceFunc(JsonPathParseItem *arg0, JsonPathParseItem *arg1)
+{
+	JsonPathParseItem *v = makeItemType(jpiReplaceFunc);
+
+	v->value.method_args.arg0 = arg0;
+	v->value.method_args.arg1 = arg1;
+
+	return v;
+}
+
+static JsonPathParseItem *
+makeItemStrSplitPartFunc(JsonPathParseItem *arg0, JsonPathParseItem *arg1)
+{
+	JsonPathParseItem *v = makeItemType(jpiStrSplitPartFunc);
+
+	v->value.method_args.arg0 = arg0;
+	v->value.method_args.arg1 = arg1;
+
+	return v;
+}
+
 static JsonPathParseItem *
 makeItemUnary(JsonPathItemType type, JsonPathParseItem *a)
 {
diff --git a/src/backend/utils/adt/jsonpath_scan.l b/src/backend/utils/adt/jsonpath_scan.l
index c7aab83eeb4..f20e9e5f1d3 100644
--- a/src/backend/utils/adt/jsonpath_scan.l
+++ b/src/backend/utils/adt/jsonpath_scan.l
@@ -433,6 +433,47 @@ static const JsonPathKeyword keywords[] = {
 	{9, false, TIMESTAMP_P, "timestamp"},
 	{10, false, LIKE_REGEX_P, "like_regex"},
 	{12, false, TIMESTAMP_TZ_P, "timestamp_tz"},
+	{ 2, false,	IS_P,		"is"},
+	{ 2, false,	TO_P,		"to"},
+	{ 3, false,	ABS_P,		"abs"},
+	{ 3, false,	LAX_P,		"lax"},
+	{ 4, false,	DATE_P,		"date"},
+	{ 4, false,	FLAG_P,		"flag"},
+	{ 4, false,	LAST_P,		"last"},
+	{ 4, true,	NULL_P,		"null"},
+	{ 4, false,	SIZE_P,		"size"},
+	{ 4, false,	TIME_P,		"time"},
+	{ 4, true,	TRUE_P,		"true"},
+	{ 4, false,	TYPE_P,		"type"},
+	{ 4, false,	WITH_P,		"with"},
+	{ 5, false, STR_BTRIM_P, "btrim"},
+	{ 5, true,	FALSE_P,	"false"},
+	{ 5, false,	FLOOR_P,	"floor"},
+	{ 5, false, STR_LOWER_P, "lower"},
+	{ 5, false, STR_LTRIM_P, "ltrim"},
+	{ 5, false, STR_RTRIM_P, "rtrim"},
+	{ 5, false, STR_UPPER_P, "upper"},
+	{ 6, false,	BIGINT_P,	"bigint"},
+	{ 6, false,	DOUBLE_P,	"double"},
+	{ 6, false,	EXISTS_P,	"exists"},
+	{ 6, false,	NUMBER_P,	"number"},
+	{ 6, false,	STARTS_P,	"starts"},
+	{ 6, false,	STRICT_P,	"strict"},
+	{ 6, false,	STRINGFUNC_P, "string"},
+	{ 7, false,	BOOLEAN_P,	"boolean"},
+	{ 7, false,	CEILING_P,	"ceiling"},
+	{ 7, false,	DECIMAL_P,	"decimal"},
+	{ 7, false, STR_INITCAP_P, "initcap"},
+	{ 7, false,	INTEGER_P,	"integer"},
+	{ 7, false, STR_REPLACEFUNC_P, "replace"},
+	{ 7, false,	TIME_TZ_P,	"time_tz"},
+	{ 7, false,	UNKNOWN_P,	"unknown"},
+	{ 8, false,	DATETIME_P,	"datetime"},
+	{ 8, false,	KEYVALUE_P,	"keyvalue"},
+	{ 9, false,	TIMESTAMP_P, "timestamp"},
+	{ 10,false, LIKE_REGEX_P, "like_regex"},
+	{ 10,false, STR_SPLIT_PART_P, "split_part"},
+	{ 12,false, TIMESTAMP_TZ_P, "timestamp_tz"},
 };
 
 /*
diff --git a/src/include/utils/jsonpath.h b/src/include/utils/jsonpath.h
index 23a76d233e9..4c60f9d1826 100644
--- a/src/include/utils/jsonpath.h
+++ b/src/include/utils/jsonpath.h
@@ -115,6 +115,14 @@ typedef enum JsonPathItemType
 	jpiTimeTz,					/* .time_tz() item method */
 	jpiTimestamp,				/* .timestamp() item method */
 	jpiTimestampTz,				/* .timestamp_tz() item method */
+	jpiReplaceFunc,				/* .replace() item method */
+	jpiStrLowerFunc,			/* .lower() item method */
+	jpiStrUpperFunc,			/* .upper() item method */
+	jpiStrLtrimFunc,			/* .ltrim() item method */
+	jpiStrRtrimFunc,			/* .rtrim() item method */
+	jpiStrBtrimFunc,			/* .btrim() item method */
+	jpiStrInitcapFunc,			/* .initcap() item method */
+	jpiStrSplitPartFunc,		/* .split_part() item method */
 } JsonPathItemType;
 
 /* XQuery regex mode flags for LIKE_REGEX predicate */
@@ -188,6 +196,12 @@ typedef struct JsonPathItem
 			int32		patternlen;
 			uint32		flags;
 		}			like_regex;
+
+		struct
+		{
+			int32		arg0;
+			int32		arg1;
+		}			method_args;
 	}			content;
 } JsonPathItem;
 
@@ -199,6 +213,8 @@ extern bool jspGetNext(JsonPathItem *v, JsonPathItem *a);
 extern void jspGetArg(JsonPathItem *v, JsonPathItem *a);
 extern void jspGetLeftArg(JsonPathItem *v, JsonPathItem *a);
 extern void jspGetRightArg(JsonPathItem *v, JsonPathItem *a);
+extern void jspGetArg0(JsonPathItem *v, JsonPathItem *a);
+extern void jspGetArg1(JsonPathItem *v, JsonPathItem *a);
 extern Numeric jspGetNumeric(JsonPathItem *v);
 extern bool jspGetBool(JsonPathItem *v);
 extern char *jspGetString(JsonPathItem *v, int32 *len);
@@ -266,6 +282,12 @@ struct JsonPathParseItem
 			uint32		len;
 			char	   *val;	/* could not be not null-terminated */
 		}			string;
+
+		struct
+		{
+			JsonPathParseItem *arg0;
+			JsonPathParseItem *arg1;
+		}			method_args;
 	}			value;
 };
 
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e91a29..2dbaec92129 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -2723,6 +2723,399 @@ select jsonb_path_query('"2023-08-15 12:34:56"', '$.timestamp().string()');
 (1 row)
 
 rollback;
+-- test .ltrim()
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('null', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('null', '$.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.ltrim()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('{}', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('true', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('1234', '$.ltrim().type()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim()');
+  jsonb_path_query_array  
+--------------------------
+ ["maybe  ", "yes", "no"]
+(1 row)
+
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .rtrim()
+select jsonb_path_query('"   hello   "', '$.rtrim(" ")');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.rtrim(" ")');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+-- test .btrim()
+select jsonb_path_query('"   hello   "', '$.btrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.btrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.btrim()');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.btrim()');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+-- test .lower()
+select jsonb_path_query('null', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('null', '$.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.lower()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('{}', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.lower()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.lower()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('true', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('1234', '$.lower().type()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower()');
+ jsonb_path_query_array 
+------------------------
+ ["maybe", "yes", "no"]
+(1 row)
+
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .upper()
+select jsonb_path_query('null', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('null', '$.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.upper()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('{}', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.upper()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.upper()');
+ jsonb_path_query 
+------------------
+ "1.23AAA"
+(1 row)
+
+select jsonb_path_query('1234', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('true', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('1234', '$.upper().type()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper()');
+ jsonb_path_query_array 
+------------------------
+ ["MAYBE", "YES", "NO"]
+(1 row)
+
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .initcap()
+select jsonb_path_query('null', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('null', '$.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.initcap()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('{}', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('true', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('1234', '$.initcap().type()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('["maybe yes", "probably no"]', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "Maybe Yes"
+ "Probably No"
+(2 rows)
+
+-- Test .replace()
+select jsonb_path_query('null', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('null', '$.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('["x", "y", "z"]', '$.replace("x", "bye")');
+ jsonb_path_query 
+------------------
+ "bye"
+ "y"
+ "z"
+(3 rows)
+
+select jsonb_path_query('{}', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('"hello world"', '$.replace("hello","bye")');
+ jsonb_path_query 
+------------------
+ "bye world"
+(1 row)
+
+select jsonb_path_query('"hello world"', '$.replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
+-- Test .split_part()
+select jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)');
+ jsonb_path_query 
+------------------
+ "def"
+(1 row)
+
+-- Test string methods play nicely together
+select jsonb_path_query('"hello world"', '$.replace("hello","bye").upper()');
+ jsonb_path_query 
+------------------
+ "BYE WORLD"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye")');
+ jsonb_path_query 
+------------------
+ "bye world"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.upper().lower().upper().replace("HELLO", "BYE")');
+ jsonb_path_query 
+------------------
+ "BYE WORLD"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
+select jsonb_path_query('"   hElLo WorlD "', '$.btrim().lower().upper().lower().replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
 -- Test .time()
 select jsonb_path_query('null', '$.time()');
 ERROR:  jsonpath item method .time() can only be applied to a string
diff --git a/src/test/regress/expected/jsonpath.out b/src/test/regress/expected/jsonpath.out
index fd9bd755f52..1b122e877d5 100644
--- a/src/test/regress/expected/jsonpath.out
+++ b/src/test/regress/expected/jsonpath.out
@@ -435,6 +435,78 @@ select '$.string()'::jsonpath;
  $.string()
 (1 row)
 
+select '$.replace("hello","bye")'::jsonpath;
+         jsonpath         
+--------------------------
+ $.replace("hello","bye")
+(1 row)
+
+select '$.lower()'::jsonpath;
+ jsonpath  
+-----------
+ $.lower()
+(1 row)
+
+select '$.upper()'::jsonpath;
+ jsonpath  
+-----------
+ $.upper()
+(1 row)
+
+select '$.lower().upper().lower().replace("hello","bye")'::jsonpath;
+                     jsonpath                     
+--------------------------------------------------
+ $.lower().upper().lower().replace("hello","bye")
+(1 row)
+
+select '$.ltrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.ltrim()
+(1 row)
+
+select '$.ltrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.ltrim("xyz")
+(1 row)
+
+select '$.rtrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.rtrim()
+(1 row)
+
+select '$.rtrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.rtrim("xyz")
+(1 row)
+
+select '$.btrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.btrim()
+(1 row)
+
+select '$.btrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.btrim("xyz")
+(1 row)
+
+select '$.initcap()'::jsonpath;
+  jsonpath   
+-------------
+ $.initcap()
+(1 row)
+
+select '$.split_part("~@~", 2)'::jsonpath;
+       jsonpath        
+-----------------------
+ $.split_part("~@~",2)
+(1 row)
+
 select '$.time()'::jsonpath;
  jsonpath 
 ----------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a5269..e229e0a0d04 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -623,6 +623,114 @@ select jsonb_path_query('"2023-08-15 12:34:56 +5:30"', '$.timestamp_tz().string(
 select jsonb_path_query('"2023-08-15 12:34:56"', '$.timestamp().string()');
 rollback;
 
+-- test .ltrim()
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+select jsonb_path_query('"   hello   "', '$.ltrim()');
+select jsonb_path_query('"   hello   "', '$.ltrim()');
+select jsonb_path_query('null', '$.ltrim()');
+select jsonb_path_query('null', '$.ltrim()', silent => true);
+select jsonb_path_query('[]', '$.ltrim()');
+select jsonb_path_query('[]', 'strict $.ltrim()');
+select jsonb_path_query('{}', '$.ltrim()');
+select jsonb_path_query('[]', 'strict $.ltrim()', silent => true);
+select jsonb_path_query('{}', '$.ltrim()', silent => true);
+select jsonb_path_query('1.23', '$.ltrim()');
+select jsonb_path_query('"1.23"', '$.ltrim()');
+select jsonb_path_query('"1.23aaa"', '$.ltrim()');
+select jsonb_path_query('1234', '$.ltrim()');
+select jsonb_path_query('true', '$.ltrim()');
+select jsonb_path_query('1234', '$.ltrim().type()');
+select jsonb_path_query('[2, true]', '$.ltrim()');
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim()');
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim().type()');
+
+-- test .rtrim()
+select jsonb_path_query('"   hello   "', '$.rtrim(" ")');
+select jsonb_path_query('"   hello   "', '$.rtrim(" ")');
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+
+-- test .btrim()
+select jsonb_path_query('"   hello   "', '$.btrim(" ")');
+select jsonb_path_query('"   hello   "', '$.btrim(" ")');
+select jsonb_path_query('"   hello   "', '$.btrim()');
+select jsonb_path_query('"   hello   "', '$.btrim()');
+
+-- test .lower()
+select jsonb_path_query('null', '$.lower()');
+select jsonb_path_query('null', '$.lower()', silent => true);
+select jsonb_path_query('[]', '$.lower()');
+select jsonb_path_query('[]', 'strict $.lower()');
+select jsonb_path_query('{}', '$.lower()');
+select jsonb_path_query('[]', 'strict $.lower()', silent => true);
+select jsonb_path_query('{}', '$.lower()', silent => true);
+select jsonb_path_query('1.23', '$.lower()');
+select jsonb_path_query('"1.23"', '$.lower()');
+select jsonb_path_query('"1.23aaa"', '$.lower()');
+select jsonb_path_query('1234', '$.lower()');
+select jsonb_path_query('true', '$.lower()');
+select jsonb_path_query('1234', '$.lower().type()');
+select jsonb_path_query('[2, true]', '$.lower()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower().type()');
+
+-- test .upper()
+select jsonb_path_query('null', '$.upper()');
+select jsonb_path_query('null', '$.upper()', silent => true);
+select jsonb_path_query('[]', '$.upper()');
+select jsonb_path_query('[]', 'strict $.upper()');
+select jsonb_path_query('{}', '$.upper()');
+select jsonb_path_query('[]', 'strict $.upper()', silent => true);
+select jsonb_path_query('{}', '$.upper()', silent => true);
+select jsonb_path_query('1.23', '$.upper()');
+select jsonb_path_query('"1.23"', '$.upper()');
+select jsonb_path_query('"1.23aaa"', '$.upper()');
+select jsonb_path_query('1234', '$.upper()');
+select jsonb_path_query('true', '$.upper()');
+select jsonb_path_query('1234', '$.upper().type()');
+select jsonb_path_query('[2, true]', '$.upper()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper().type()');
+
+-- test .initcap()
+select jsonb_path_query('null', '$.initcap()');
+select jsonb_path_query('null', '$.initcap()', silent => true);
+select jsonb_path_query('[]', '$.initcap()');
+select jsonb_path_query('[]', 'strict $.initcap()');
+select jsonb_path_query('{}', '$.initcap()');
+select jsonb_path_query('[]', 'strict $.initcap()', silent => true);
+select jsonb_path_query('{}', '$.initcap()', silent => true);
+select jsonb_path_query('1.23', '$.initcap()');
+select jsonb_path_query('"1.23"', '$.initcap()');
+select jsonb_path_query('"1.23aaa"', '$.initcap()');
+select jsonb_path_query('1234', '$.initcap()');
+select jsonb_path_query('true', '$.initcap()');
+select jsonb_path_query('1234', '$.initcap().type()');
+select jsonb_path_query('[2, true]', '$.initcap()');
+select jsonb_path_query('["maybe yes", "probably no"]', '$.initcap()');
+
+-- Test .replace()
+select jsonb_path_query('null', '$.replace("x", "bye")');
+select jsonb_path_query('null', '$.replace("x", "bye")', silent => true);
+select jsonb_path_query('["x", "y", "z"]', '$.replace("x", "bye")');
+select jsonb_path_query('{}', '$.replace("x", "bye")');
+select jsonb_path_query('[]', 'strict $.replace("x", "bye")', silent => true);
+select jsonb_path_query('{}', '$.replace("x", "bye")', silent => true);
+select jsonb_path_query('1.23', '$.replace("x", "bye")');
+select jsonb_path_query('"hello world"', '$.replace("hello","bye")');
+select jsonb_path_query('"hello world"', '$.replace("hello","bye") starts with "bye"');
+
+-- Test .split_part()
+select jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)');
+
+-- Test string methods play nicely together
+select jsonb_path_query('"hello world"', '$.replace("hello","bye").upper()');
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye")');
+select jsonb_path_query('"hElLo WorlD"', '$.upper().lower().upper().replace("HELLO", "BYE")');
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye") starts with "bye"');
+select jsonb_path_query('"   hElLo WorlD "', '$.btrim().lower().upper().lower().replace("hello","bye") starts with "bye"');
+
 -- Test .time()
 select jsonb_path_query('null', '$.time()');
 select jsonb_path_query('true', '$.time()');
diff --git a/src/test/regress/sql/jsonpath.sql b/src/test/regress/sql/jsonpath.sql
index 61a5270d4e8..8752ffcf08c 100644
--- a/src/test/regress/sql/jsonpath.sql
+++ b/src/test/regress/sql/jsonpath.sql
@@ -78,6 +78,19 @@ select '$.boolean()'::jsonpath;
 select '$.date()'::jsonpath;
 select '$.decimal(4,2)'::jsonpath;
 select '$.string()'::jsonpath;
+select '$.replace("hello","bye")'::jsonpath;
+select '$.lower()'::jsonpath;
+select '$.upper()'::jsonpath;
+select '$.lower().upper().lower().replace("hello","bye")'::jsonpath;
+select '$.ltrim()'::jsonpath;
+select '$.ltrim("xyz")'::jsonpath;
+select '$.rtrim()'::jsonpath;
+select '$.rtrim("xyz")'::jsonpath;
+select '$.btrim()'::jsonpath;
+select '$.btrim("xyz")'::jsonpath;
+select '$.initcap()'::jsonpath;
+select '$.split_part("~@~", 2)'::jsonpath;
+
 select '$.time()'::jsonpath;
 select '$.time(6)'::jsonpath;
 select '$.time_tz()'::jsonpath;
-- 
2.49.0

From 6c61d2190fe0bef195032f4adcf50f7ddcc82bf5 Mon Sep 17 00:00:00 2001
From: Florents Tselai <florents.tselai@gmail.com>
Date: Sat, 24 May 2025 17:59:54 -0400
Subject: [PATCH v5] Add additional jsonpath string methods

Add the following jsonpath methods:

*   l/r/btrim()
*   lower(), upper()
*   initcap()
*   replace()
*   split_part()

Each simply dispatches to the standard string processing functions.
These depend on the locale, but since it's set at `initdb`, they can be
considered immutable and therefore allowed in any jsonpath expression.
---
 doc/src/sgml/func.sgml                       | 171 ++++++++
 src/backend/utils/adt/jsonpath.c             | 176 ++++++++-
 src/backend/utils/adt/jsonpath_exec.c        | 189 +++++++++
 src/backend/utils/adt/jsonpath_gram.y        |  71 +++-
 src/backend/utils/adt/jsonpath_scan.l        |   8 +
 src/include/utils/jsonpath.h                 |  22 ++
 src/test/regress/expected/jsonb_jsonpath.out | 393 +++++++++++++++++++
 src/test/regress/expected/jsonpath.out       |  72 ++++
 src/test/regress/sql/jsonb_jsonpath.sql      | 108 +++++
 src/test/regress/sql/jsonpath.sql            |  13 +
 10 files changed, 1219 insertions(+), 4 deletions(-)

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index c67688cbf5f..25d0d920dbf 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -18627,6 +18627,177 @@ ERROR:  jsonpath member accessor can only be applied to an object
         <returnvalue>[{"id": 0, "key": "x", "value": "20"}, {"id": 0, "key": "y", "value": 32}]</returnvalue>
        </para></entry>
       </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>lower()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String converted to all lower case according to the rules of the database's locale.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"TOM"', '$.lower()')</literal>
+        <returnvalue>"tom"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>upper()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String converted to all upper case according to the rules of the database's locale.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"tom"', '$.upper()')</literal>
+        <returnvalue>"TOM"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>initcap()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the first letter of each word converted to upper case
+        according to the rules of the database's locale. Words are sequences
+        of alphanumeric characters separated by non-alphanumeric characters.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"hi THOMAS"', '$.initcap()')</literal>
+        <returnvalue>"Hi Thomas"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>replace(<replaceable>from</replaceable>, <replaceable>to</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with all occurrences of substring from replaced with substring to.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"abcdefabcdef"', '$.replace("cd", "XX")')</literal>
+        <returnvalue>"abXXefabXXef"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>split_part(<replaceable>delimiter</replaceable>, <replaceable>n</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String split at occurrences of <replaceable>delimiter</replaceable>
+        and returns the <replaceable>n</replaceable>'th field (counting from
+        one) or, when <replaceable>n</replaceable> is negative, returns the
+        |<replaceable>n</replaceable>|'th-from-last field.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)')</literal>
+        <returnvalue>"def"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"abc,def,ghi,jkl"', '$.split_part(",", 2)')</literal>
+        <returnvalue>"ghi"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>ltrim()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with spaces removed from the start of <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal> jsonb_path_query('"  hello"', '$.ltrim()')</literal>
+        <returnvalue>"hello"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>ltrim(<replaceable>characters</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the longest string containing only characters in
+        <replaceable>characters</replaceable> removed from the start of
+        <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"zzzytest"', '$.ltrim("xyz")')</literal>
+        <returnvalue>"test"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>rtrim()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with spaces removed from the end of <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"hello  "', '$.rtrim()')</literal>
+        <returnvalue>"hello"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>rtrim(<replaceable>characters</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the longest string containing only characters in
+        <replaceable>characters</replaceable> removed from the end of
+        <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"testxxzx"', '$.rtrim("xyz")')</literal>
+        <returnvalue>"test"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>btrim()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with spaces removed from the start and end of
+        <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"  hello  "', '$.btrim()')</literal>
+        <returnvalue>"hello"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>btrim(<replaceable>characters</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the longest string containing only characters in
+        <replaceable>characters</replaceable> removed from the start and end
+        of <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"xyxtrimyyx"', '$.btrim("xyz")')</literal>
+        <returnvalue>"trim"</returnvalue>
+       </para></entry>
+      </row>
+
      </tbody>
     </tgroup>
    </table>
diff --git a/src/backend/utils/adt/jsonpath.c b/src/backend/utils/adt/jsonpath.c
index 762f7e8a09d..646c7b460a3 100644
--- a/src/backend/utils/adt/jsonpath.c
+++ b/src/backend/utils/adt/jsonpath.c
@@ -326,6 +326,38 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 				*(int32 *) (buf->data + right) = chld - pos;
 			}
 			break;
+		case jpiReplaceFunc:
+		case jpiStrSplitPartFunc:
+		{
+			{
+				/*
+				 * First, reserve place for left/right arg's positions, then
+				 * record both args and sets actual position in reserved
+				 * places.
+				 */
+				int32		arg0 = reserveSpaceForItemPointer(buf);
+				int32		arg1 = reserveSpaceForItemPointer(buf);
+
+				if (!item->value.method_args.arg0)
+					chld = pos;
+				else if (!flattenJsonPathParseItem(buf, &chld, escontext,
+												   item->value.method_args.arg0,
+												   nestingLevel + argNestingLevel,
+												   insideArraySubscript))
+					return false;
+				*(int32 *) (buf->data + arg0) = chld - pos;
+
+				if (!item->value.method_args.arg1)
+					chld = pos;
+				else if (!flattenJsonPathParseItem(buf, &chld, escontext,
+												   item->value.method_args.arg1,
+												   nestingLevel + argNestingLevel,
+												   insideArraySubscript))
+					return false;
+				*(int32 *) (buf->data + arg1) = chld - pos;
+			}
+		}
+		break;
 		case jpiLikeRegex:
 			{
 				int32		offs;
@@ -362,6 +394,9 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 		case jpiTimeTz:
 		case jpiTimestamp:
 		case jpiTimestampTz:
+		case jpiStrLtrimFunc:
+		case jpiStrRtrimFunc:
+		case jpiStrBtrimFunc:
 			{
 				int32		arg = reserveSpaceForItemPointer(buf);
 
@@ -457,6 +492,9 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 		case jpiInteger:
 		case jpiNumber:
 		case jpiStringFunc:
+		case jpiStrLowerFunc:
+		case jpiStrUpperFunc:
+		case jpiStrInitcapFunc:
 			break;
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", item->type);
@@ -831,6 +869,72 @@ printJsonPathItem(StringInfo buf, JsonPathItem *v, bool inKey,
 			}
 			appendStringInfoChar(buf, ')');
 			break;
+		case jpiReplaceFunc:
+			appendStringInfoString(buf, ".replace(");
+			if (v->content.method_args.arg0)
+			{
+				jspGetArg0(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			if (v->content.method_args.arg1)
+			{
+				appendStringInfoChar(buf, ',');
+				jspGetArg1(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrSplitPartFunc:
+			appendStringInfoString(buf, ".split_part(");
+			if (v->content.method_args.arg0)
+			{
+				jspGetArg0(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			if (v->content.method_args.arg1)
+			{
+				appendStringInfoChar(buf, ',');
+				jspGetArg1(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrLowerFunc:
+			appendStringInfoString(buf, ".lower()");
+			break;
+		case jpiStrUpperFunc:
+			appendStringInfoString(buf, ".upper()");
+			break;
+		case jpiStrInitcapFunc:
+			appendStringInfoString(buf, ".initcap()");
+			break;
+		case jpiStrLtrimFunc:
+			appendStringInfoString(buf, ".ltrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrRtrimFunc:
+			appendStringInfoString(buf, ".rtrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrBtrimFunc:
+			appendStringInfoString(buf, ".btrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", v->type);
 	}
@@ -906,6 +1010,12 @@ jspOperationName(JsonPathItemType type)
 			return "number";
 		case jpiStringFunc:
 			return "string";
+		case jpiReplaceFunc:
+			return "replace";
+		case jpiStrLowerFunc:
+			return "lower";
+		case jpiStrUpperFunc:
+			return "upper";
 		case jpiTime:
 			return "time";
 		case jpiTimeTz:
@@ -914,6 +1024,16 @@ jspOperationName(JsonPathItemType type)
 			return "timestamp";
 		case jpiTimestampTz:
 			return "timestamp_tz";
+		case jpiStrLtrimFunc:
+			return "ltrim";
+		case jpiStrRtrimFunc:
+			return "rtrim";
+		case jpiStrBtrimFunc:
+			return "btrim";
+		case jpiStrInitcapFunc:
+			return "initcap";
+		case jpiStrSplitPartFunc:
+			return "split_part";
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", type);
 			return NULL;
@@ -1016,6 +1136,9 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 		case jpiInteger:
 		case jpiNumber:
 		case jpiStringFunc:
+		case jpiStrLowerFunc:
+		case jpiStrUpperFunc:
+		case jpiStrInitcapFunc:
 			break;
 		case jpiString:
 		case jpiKey:
@@ -1044,6 +1167,11 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 			read_int32(v->content.args.left, base, pos);
 			read_int32(v->content.args.right, base, pos);
 			break;
+		case jpiReplaceFunc:
+		case jpiStrSplitPartFunc:
+			read_int32(v->content.method_args.arg0, base, pos);
+			read_int32(v->content.method_args.arg1, base, pos);
+		break;
 		case jpiNot:
 		case jpiIsUnknown:
 		case jpiExists:
@@ -1055,6 +1183,9 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 		case jpiTimeTz:
 		case jpiTimestamp:
 		case jpiTimestampTz:
+		case jpiStrLtrimFunc:
+		case jpiStrRtrimFunc:
+		case jpiStrBtrimFunc:
 			read_int32(v->content.arg, base, pos);
 			break;
 		case jpiIndexArray:
@@ -1090,7 +1221,10 @@ jspGetArg(JsonPathItem *v, JsonPathItem *a)
 		   v->type == jpiTime ||
 		   v->type == jpiTimeTz ||
 		   v->type == jpiTimestamp ||
-		   v->type == jpiTimestampTz);
+		   v->type == jpiTimestampTz ||
+		   v->type == jpiStrLtrimFunc ||
+		   v->type == jpiStrRtrimFunc ||
+		   v->type == jpiStrBtrimFunc);
 
 	jspInitByBuffer(a, v->base, v->content.arg);
 }
@@ -1149,10 +1283,18 @@ jspGetNext(JsonPathItem *v, JsonPathItem *a)
 			   v->type == jpiInteger ||
 			   v->type == jpiNumber ||
 			   v->type == jpiStringFunc ||
+			   v->type == jpiReplaceFunc ||
+			   v->type == jpiStrLowerFunc ||
+			   v->type == jpiStrUpperFunc ||
 			   v->type == jpiTime ||
 			   v->type == jpiTimeTz ||
 			   v->type == jpiTimestamp ||
-			   v->type == jpiTimestampTz);
+			   v->type == jpiTimestampTz ||
+			   v->type == jpiStrLtrimFunc ||
+			   v->type == jpiStrRtrimFunc ||
+			   v->type == jpiStrBtrimFunc ||
+			   v->type == jpiStrInitcapFunc ||
+			   v->type == jpiStrSplitPartFunc);
 
 		if (a)
 			jspInitByBuffer(a, v->base, v->nextPos);
@@ -1184,6 +1326,24 @@ jspGetLeftArg(JsonPathItem *v, JsonPathItem *a)
 	jspInitByBuffer(a, v->base, v->content.args.left);
 }
 
+void
+jspGetArg0(JsonPathItem *v, JsonPathItem *a)
+{
+	Assert(v->type == jpiReplaceFunc ||
+			v->type == jpiStrSplitPartFunc);
+
+	jspInitByBuffer(a, v->base, v->content.method_args.arg0);
+}
+
+void
+jspGetArg1(JsonPathItem *v, JsonPathItem *a)
+{
+	Assert(v->type == jpiReplaceFunc ||
+			v->type == jpiStrSplitPartFunc);
+
+	jspInitByBuffer(a, v->base, v->content.method_args.arg1);
+}
+
 void
 jspGetRightArg(JsonPathItem *v, JsonPathItem *a)
 {
@@ -1206,6 +1366,7 @@ jspGetRightArg(JsonPathItem *v, JsonPathItem *a)
 	jspInitByBuffer(a, v->base, v->content.args.right);
 }
 
+
 bool
 jspGetBool(JsonPathItem *v)
 {
@@ -1227,7 +1388,8 @@ jspGetString(JsonPathItem *v, int32 *len)
 {
 	Assert(v->type == jpiKey ||
 		   v->type == jpiString ||
-		   v->type == jpiVariable);
+		   v->type == jpiVariable ||
+		   v->type == jpiStringFunc);
 
 	if (len)
 		*len = v->content.value.datalen;
@@ -1501,6 +1663,14 @@ jspIsMutableWalker(JsonPathItem *jpi, struct JsonPathMutableContext *cxt)
 			case jpiInteger:
 			case jpiNumber:
 			case jpiStringFunc:
+			case jpiReplaceFunc:
+			case jpiStrLowerFunc:
+			case jpiStrUpperFunc:
+			case jpiStrLtrimFunc:
+			case jpiStrRtrimFunc:
+			case jpiStrBtrimFunc:
+			case jpiStrInitcapFunc:
+			case jpiStrSplitPartFunc:
 				status = jpdsNonDateTime;
 				break;
 
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index dbab24737ef..51239121f18 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -301,6 +301,8 @@ static JsonPathExecResult executeNumericItemMethod(JsonPathExecContext *cxt,
 												   JsonValueList *found);
 static JsonPathExecResult executeDateTimeMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
 												JsonbValue *jb, JsonValueList *found);
+static JsonPathExecResult executeStringInternalMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
+												JsonbValue *jb, JsonValueList *found);
 static JsonPathExecResult executeKeyValueMethod(JsonPathExecContext *cxt,
 												JsonPathItem *jsp, JsonbValue *jb, JsonValueList *found);
 static JsonPathExecResult appendBoolResult(JsonPathExecContext *cxt,
@@ -1659,6 +1661,23 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
 			}
 			break;
 
+		case jpiStrLtrimFunc:
+		case jpiStrLowerFunc:
+		case jpiStrUpperFunc:
+		case jpiReplaceFunc:
+		case jpiStrRtrimFunc:
+		case jpiStrBtrimFunc:
+		case jpiStrInitcapFunc:
+		case jpiStrSplitPartFunc:
+		{
+			if (unwrap && JsonbType(jb) == jbvArray)
+				return executeItemUnwrapTargetArray(cxt, jsp, jb, found, false);
+
+			return executeStringInternalMethod(cxt, jsp, jb, found);
+		}
+		break;
+
+
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", jsp->type);
 	}
@@ -2792,6 +2811,176 @@ executeDateTimeMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
 	return executeNextItem(cxt, jsp, &elem, jb, found, hasNext);
 }
 
+/*
+ * Implementation of .upper(), lower() et. al. methods,
+ * that forward their actual implementation to internal functions.
+ */
+static JsonPathExecResult executeStringInternalMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
+												JsonbValue *jb, JsonValueList *found) {
+	Assert(	jsp->type == jpiStrLowerFunc ||
+			jsp->type == jpiStrUpperFunc ||
+			jsp->type == jpiReplaceFunc ||
+			jsp->type == jpiStrLtrimFunc ||
+			jsp->type == jpiStrRtrimFunc ||
+			jsp->type == jpiStrBtrimFunc ||
+			jsp->type == jpiStrInitcapFunc ||
+			jsp->type == jpiStrSplitPartFunc);
+	JsonbValue	jbvbuf;
+	bool		hasNext;
+	JsonPathExecResult res = jperNotFound;
+	JsonPathItem elem;
+	Datum		str; /* Datum representation for the current string value. The first argument to internal functions */
+	char		*tmp = NULL;
+	char		*resStr = NULL;
+
+	if (!(jb = getScalar(jb, jbvString)))
+		RETURN_ERROR(ereport(ERROR,
+							 (errcode(ERRCODE_INVALID_ARGUMENT_FOR_SQL_JSON_DATETIME_FUNCTION),
+							  errmsg("jsonpath item method .%s() can only be applied to a string",
+									 jspOperationName(jsp->type)))));
+
+	tmp = pnstrdup(jb->val.string.val, jb->val.string.len);
+	str = CStringGetTextDatum(tmp);
+
+	/* Internal string functions that accept no arguments */
+	switch (jsp->type)
+	{
+		case jpiStrLtrimFunc:
+		case jpiStrRtrimFunc:
+		case jpiStrBtrimFunc:
+		{
+			char	   *characters_str;
+			int			characters_len;
+			PGFunction	func = NULL;
+
+			switch (jsp->type)
+			{
+				case jpiStrLtrimFunc:
+					func = ltrim1;
+					break;
+				case jpiStrRtrimFunc:
+					func = rtrim1;
+					break;
+				case jpiStrBtrimFunc:
+					func = btrim1;
+					break;
+				default: ;
+			}
+
+			if (jsp->content.arg)
+			{
+				jspGetArg(jsp, &elem);
+				if (elem.type != jpiString)
+					elog(ERROR, "invalid jsonpath item type for .%s() argument", jspOperationName(jsp->type));
+
+				characters_str = jspGetString(&elem, &characters_len);
+				resStr = TextDatumGetCString(DirectFunctionCall2Coll(func,
+					DEFAULT_COLLATION_OID, str,
+					CStringGetTextDatum(characters_str)));
+				break;
+			}
+
+			resStr = TextDatumGetCString(DirectFunctionCall2Coll(func,
+					DEFAULT_COLLATION_OID, str,
+					CStringGetTextDatum(" ")));
+			break;
+		}
+
+		case jpiStrLowerFunc:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(lower, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiStrUpperFunc:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(upper, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiStrInitcapFunc:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(initcap, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiReplaceFunc:
+		{
+			char		*from_str, *to_str;
+			int			from_len, to_len;
+
+			jspGetArg0(jsp, &elem);
+			if (elem.type != jpiString)
+				elog(ERROR, "invalid jsonpath item type for .replace() from");
+
+			from_str = jspGetString(&elem, &from_len);
+
+			jspGetArg1(jsp, &elem);
+			if (elem.type != jpiString)
+				elog(ERROR, "invalid jsonpath item type for .replace() to");
+
+			to_str = jspGetString(&elem, &to_len);
+
+			resStr = TextDatumGetCString(DirectFunctionCall3Coll(replace_text,
+				C_COLLATION_OID,
+				CStringGetTextDatum(tmp),
+				CStringGetTextDatum(from_str),
+				CStringGetTextDatum(to_str)));
+			break;
+		}
+		case jpiStrSplitPartFunc:
+		{
+			char		*from_str;
+			Numeric		n;
+			int			from_len;
+
+			jspGetArg0(jsp, &elem);
+			if (elem.type != jpiString)
+				elog(ERROR, "invalid jsonpath item type for .split_part()");
+
+			from_str = jspGetString(&elem, &from_len);
+
+			jspGetArg1(jsp, &elem);
+			if (elem.type != jpiNumeric)
+				elog(ERROR, "invalid jsonpath item type for .split_part()");
+
+			n = jspGetNumeric(&elem);
+
+			resStr = TextDatumGetCString(DirectFunctionCall3Coll(split_part,
+				C_COLLATION_OID,
+				CStringGetTextDatum(tmp),
+				CStringGetTextDatum(from_str),
+				DirectFunctionCall1(numeric_int8, NumericGetDatum(n))));
+			break;
+		}
+		default:
+			elog(ERROR, "unsupported jsonpath item type: %d", jsp->type);
+	}
+
+	if (resStr)
+		res = jperOk;
+
+	hasNext = jspGetNext(jsp, &elem);
+
+	if (!hasNext && !found)
+		return res;
+
+	jb = hasNext ? &jbvbuf : palloc(sizeof(*jb));
+
+	/* Create the appropriate jb value to return */
+	switch (jsp->type)
+	{
+		/* Cases for functions that return text */
+		case jpiStrLowerFunc:
+		case jpiStrUpperFunc:
+		case jpiReplaceFunc:
+		case jpiStrLtrimFunc:
+		case jpiStrRtrimFunc:
+		case jpiStrBtrimFunc:
+		case jpiStrInitcapFunc:
+		case jpiStrSplitPartFunc:
+			jb->type = jbvString;
+			jb->val.string.val = resStr;
+			jb->val.string.len = strlen(jb->val.string.val);
+		default:
+			;
+			/* cant' happen */
+	}
+
+	return executeNextItem(cxt, jsp, &elem, jb, found, hasNext);
+}
+
 /*
  * Implementation of .keyvalue() method.
  *
diff --git a/src/backend/utils/adt/jsonpath_gram.y b/src/backend/utils/adt/jsonpath_gram.y
index 499745a8fef..c998c40cfbd 100644
--- a/src/backend/utils/adt/jsonpath_gram.y
+++ b/src/backend/utils/adt/jsonpath_gram.y
@@ -43,6 +43,9 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 							  JsonPathString *flags,
 							  JsonPathParseItem ** result,
 							  struct Node *escontext);
+static JsonPathParseItem *makeItemReplaceFunc(JsonPathParseItem *arg0, JsonPathParseItem *arg1);
+static JsonPathParseItem *makeItemStrSplitPartFunc(JsonPathParseItem *arg0, JsonPathParseItem *arg1);
+
 
 /*
  * Bison doesn't allocate anything that needs to live across parser calls,
@@ -86,6 +89,8 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 %token	<str>		DATETIME_P
 %token	<str>		BIGINT_P BOOLEAN_P DATE_P DECIMAL_P INTEGER_P NUMBER_P
 %token	<str>		STRINGFUNC_P TIME_P TIME_TZ_P TIMESTAMP_P TIMESTAMP_TZ_P
+%token	<str>		STR_REPLACEFUNC_P STR_LOWER_P STR_UPPER_P STR_LTRIM_P STR_RTRIM_P STR_BTRIM_P
+					STR_INITCAP_P STR_SPLIT_PART_P
 
 %type	<result>	result
 
@@ -94,8 +99,9 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 					index_elem starts_with_initial expr_or_predicate
 					datetime_template opt_datetime_template csv_elem
 					datetime_precision opt_datetime_precision
+					str_method_arg_elem
 
-%type	<elems>		accessor_expr csv_list opt_csv_list
+%type	<elems>		accessor_expr csv_list opt_csv_list str_method_arg_list
 
 %type	<indexs>	index_list
 
@@ -278,6 +284,32 @@ accessor_op:
 		{ $$ = makeItemUnary(jpiTimestamp, $4); }
 	| '.' TIMESTAMP_TZ_P '(' opt_datetime_precision ')'
 		{ $$ = makeItemUnary(jpiTimestampTz, $4); }
+	| '.' STR_REPLACEFUNC_P '(' str_method_arg_list ')'
+		{
+			if (list_length($4) == 2)
+				$$ = makeItemReplaceFunc(linitial($4), lsecond($4));
+			else
+				ereturn(escontext, false,
+						(errcode(ERRCODE_SYNTAX_ERROR),
+						 errmsg("invalid input syntax for type %s", "jsonpath"),
+						 errdetail(".replace() accepts two arguments.")));
+		}
+	| '.' STR_SPLIT_PART_P '(' str_method_arg_list ')'
+		{
+			if (list_length($4) == 2)
+				$$ = makeItemStrSplitPartFunc(linitial($4), lsecond($4));
+			else
+				ereturn(escontext, false,
+						(errcode(ERRCODE_SYNTAX_ERROR),
+						 errmsg("invalid input syntax for type %s", "jsonpath"),
+						 errdetail(".split_part() accepts two arguments.")));
+		}
+	| '.' STR_LTRIM_P '(' opt_datetime_template ')'
+		{ $$ = makeItemUnary(jpiStrLtrimFunc, $4); }
+	| '.' STR_RTRIM_P '(' opt_datetime_template ')'
+		{ $$ = makeItemUnary(jpiStrRtrimFunc, $4); }
+	| '.' STR_BTRIM_P '(' opt_datetime_template ')'
+		{ $$ = makeItemUnary(jpiStrBtrimFunc, $4); }
 	;
 
 csv_elem:
@@ -317,6 +349,15 @@ opt_datetime_template:
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
+str_method_arg_elem:
+	STRING_P						{ $$ = makeItemString(&$1); }
+	| INT_P							{ $$ = makeItemNumeric(&$1); }
+	;
+
+str_method_arg_list:
+	str_method_arg_elem							{ $$ = list_make1($1); }
+	| str_method_arg_list ',' str_method_arg_elem	{ $$ = lappend($1, $3); }
+	;
 key:
 	key_name						{ $$ = makeItemKey(&$1); }
 	;
@@ -357,6 +398,9 @@ key_name:
 	| TIME_TZ_P
 	| TIMESTAMP_P
 	| TIMESTAMP_TZ_P
+	| STR_LTRIM_P
+	| STR_RTRIM_P
+	| STR_BTRIM_P
 	;
 
 method:
@@ -373,6 +417,9 @@ method:
 	| INTEGER_P						{ $$ = jpiInteger; }
 	| NUMBER_P						{ $$ = jpiNumber; }
 	| STRINGFUNC_P					{ $$ = jpiStringFunc; }
+	| STR_LOWER_P					{ $$ = jpiStrLowerFunc; }
+	| STR_UPPER_P					{ $$ = jpiStrUpperFunc; }
+	| STR_INITCAP_P					{ $$ = jpiStrInitcapFunc; }
 	;
 %%
 
@@ -472,6 +519,28 @@ makeItemBinary(JsonPathItemType type, JsonPathParseItem *la, JsonPathParseItem *
 	return v;
 }
 
+static JsonPathParseItem *
+makeItemReplaceFunc(JsonPathParseItem *arg0, JsonPathParseItem *arg1)
+{
+	JsonPathParseItem *v = makeItemType(jpiReplaceFunc);
+
+	v->value.method_args.arg0 = arg0;
+	v->value.method_args.arg1 = arg1;
+
+	return v;
+}
+
+static JsonPathParseItem *
+makeItemStrSplitPartFunc(JsonPathParseItem *arg0, JsonPathParseItem *arg1)
+{
+	JsonPathParseItem *v = makeItemType(jpiStrSplitPartFunc);
+
+	v->value.method_args.arg0 = arg0;
+	v->value.method_args.arg1 = arg1;
+
+	return v;
+}
+
 static JsonPathParseItem *
 makeItemUnary(JsonPathItemType type, JsonPathParseItem *a)
 {
diff --git a/src/backend/utils/adt/jsonpath_scan.l b/src/backend/utils/adt/jsonpath_scan.l
index c7aab83eeb4..f12d358e81d 100644
--- a/src/backend/utils/adt/jsonpath_scan.l
+++ b/src/backend/utils/adt/jsonpath_scan.l
@@ -415,6 +415,11 @@ static const JsonPathKeyword keywords[] = {
 	{4, false, WITH_P, "with"},
 	{5, true, FALSE_P, "false"},
 	{5, false, FLOOR_P, "floor"},
+	{5, false, STR_BTRIM_P, "btrim"},
+	{5, false, STR_LOWER_P, "lower"},
+	{5, false, STR_LTRIM_P, "ltrim"},
+	{5, false, STR_RTRIM_P, "rtrim"},
+	{5, false, STR_UPPER_P, "upper"},
 	{6, false, BIGINT_P, "bigint"},
 	{6, false, DOUBLE_P, "double"},
 	{6, false, EXISTS_P, "exists"},
@@ -428,10 +433,13 @@ static const JsonPathKeyword keywords[] = {
 	{7, false, INTEGER_P, "integer"},
 	{7, false, TIME_TZ_P, "time_tz"},
 	{7, false, UNKNOWN_P, "unknown"},
+	{7, false, STR_INITCAP_P, "initcap"},
+	{7, false, STR_REPLACEFUNC_P, "replace"},
 	{8, false, DATETIME_P, "datetime"},
 	{8, false, KEYVALUE_P, "keyvalue"},
 	{9, false, TIMESTAMP_P, "timestamp"},
 	{10, false, LIKE_REGEX_P, "like_regex"},
+	{10,false, STR_SPLIT_PART_P, "split_part"},
 	{12, false, TIMESTAMP_TZ_P, "timestamp_tz"},
 };
 
diff --git a/src/include/utils/jsonpath.h b/src/include/utils/jsonpath.h
index 23a76d233e9..4c60f9d1826 100644
--- a/src/include/utils/jsonpath.h
+++ b/src/include/utils/jsonpath.h
@@ -115,6 +115,14 @@ typedef enum JsonPathItemType
 	jpiTimeTz,					/* .time_tz() item method */
 	jpiTimestamp,				/* .timestamp() item method */
 	jpiTimestampTz,				/* .timestamp_tz() item method */
+	jpiReplaceFunc,				/* .replace() item method */
+	jpiStrLowerFunc,			/* .lower() item method */
+	jpiStrUpperFunc,			/* .upper() item method */
+	jpiStrLtrimFunc,			/* .ltrim() item method */
+	jpiStrRtrimFunc,			/* .rtrim() item method */
+	jpiStrBtrimFunc,			/* .btrim() item method */
+	jpiStrInitcapFunc,			/* .initcap() item method */
+	jpiStrSplitPartFunc,		/* .split_part() item method */
 } JsonPathItemType;
 
 /* XQuery regex mode flags for LIKE_REGEX predicate */
@@ -188,6 +196,12 @@ typedef struct JsonPathItem
 			int32		patternlen;
 			uint32		flags;
 		}			like_regex;
+
+		struct
+		{
+			int32		arg0;
+			int32		arg1;
+		}			method_args;
 	}			content;
 } JsonPathItem;
 
@@ -199,6 +213,8 @@ extern bool jspGetNext(JsonPathItem *v, JsonPathItem *a);
 extern void jspGetArg(JsonPathItem *v, JsonPathItem *a);
 extern void jspGetLeftArg(JsonPathItem *v, JsonPathItem *a);
 extern void jspGetRightArg(JsonPathItem *v, JsonPathItem *a);
+extern void jspGetArg0(JsonPathItem *v, JsonPathItem *a);
+extern void jspGetArg1(JsonPathItem *v, JsonPathItem *a);
 extern Numeric jspGetNumeric(JsonPathItem *v);
 extern bool jspGetBool(JsonPathItem *v);
 extern char *jspGetString(JsonPathItem *v, int32 *len);
@@ -266,6 +282,12 @@ struct JsonPathParseItem
 			uint32		len;
 			char	   *val;	/* could not be not null-terminated */
 		}			string;
+
+		struct
+		{
+			JsonPathParseItem *arg0;
+			JsonPathParseItem *arg1;
+		}			method_args;
 	}			value;
 };
 
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e91a29..2dbaec92129 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -2723,6 +2723,399 @@ select jsonb_path_query('"2023-08-15 12:34:56"', '$.timestamp().string()');
 (1 row)
 
 rollback;
+-- test .ltrim()
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('null', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('null', '$.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.ltrim()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('{}', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('true', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('1234', '$.ltrim().type()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim()');
+  jsonb_path_query_array  
+--------------------------
+ ["maybe  ", "yes", "no"]
+(1 row)
+
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .rtrim()
+select jsonb_path_query('"   hello   "', '$.rtrim(" ")');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.rtrim(" ")');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+-- test .btrim()
+select jsonb_path_query('"   hello   "', '$.btrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.btrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.btrim()');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.btrim()');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+-- test .lower()
+select jsonb_path_query('null', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('null', '$.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.lower()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('{}', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.lower()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.lower()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('true', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('1234', '$.lower().type()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower()');
+ jsonb_path_query_array 
+------------------------
+ ["maybe", "yes", "no"]
+(1 row)
+
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .upper()
+select jsonb_path_query('null', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('null', '$.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.upper()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('{}', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.upper()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.upper()');
+ jsonb_path_query 
+------------------
+ "1.23AAA"
+(1 row)
+
+select jsonb_path_query('1234', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('true', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('1234', '$.upper().type()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper()');
+ jsonb_path_query_array 
+------------------------
+ ["MAYBE", "YES", "NO"]
+(1 row)
+
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .initcap()
+select jsonb_path_query('null', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('null', '$.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.initcap()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('{}', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('true', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('1234', '$.initcap().type()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('["maybe yes", "probably no"]', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "Maybe Yes"
+ "Probably No"
+(2 rows)
+
+-- Test .replace()
+select jsonb_path_query('null', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('null', '$.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('["x", "y", "z"]', '$.replace("x", "bye")');
+ jsonb_path_query 
+------------------
+ "bye"
+ "y"
+ "z"
+(3 rows)
+
+select jsonb_path_query('{}', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('"hello world"', '$.replace("hello","bye")');
+ jsonb_path_query 
+------------------
+ "bye world"
+(1 row)
+
+select jsonb_path_query('"hello world"', '$.replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
+-- Test .split_part()
+select jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)');
+ jsonb_path_query 
+------------------
+ "def"
+(1 row)
+
+-- Test string methods play nicely together
+select jsonb_path_query('"hello world"', '$.replace("hello","bye").upper()');
+ jsonb_path_query 
+------------------
+ "BYE WORLD"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye")');
+ jsonb_path_query 
+------------------
+ "bye world"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.upper().lower().upper().replace("HELLO", "BYE")');
+ jsonb_path_query 
+------------------
+ "BYE WORLD"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
+select jsonb_path_query('"   hElLo WorlD "', '$.btrim().lower().upper().lower().replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
 -- Test .time()
 select jsonb_path_query('null', '$.time()');
 ERROR:  jsonpath item method .time() can only be applied to a string
diff --git a/src/test/regress/expected/jsonpath.out b/src/test/regress/expected/jsonpath.out
index fd9bd755f52..1b122e877d5 100644
--- a/src/test/regress/expected/jsonpath.out
+++ b/src/test/regress/expected/jsonpath.out
@@ -435,6 +435,78 @@ select '$.string()'::jsonpath;
  $.string()
 (1 row)
 
+select '$.replace("hello","bye")'::jsonpath;
+         jsonpath         
+--------------------------
+ $.replace("hello","bye")
+(1 row)
+
+select '$.lower()'::jsonpath;
+ jsonpath  
+-----------
+ $.lower()
+(1 row)
+
+select '$.upper()'::jsonpath;
+ jsonpath  
+-----------
+ $.upper()
+(1 row)
+
+select '$.lower().upper().lower().replace("hello","bye")'::jsonpath;
+                     jsonpath                     
+--------------------------------------------------
+ $.lower().upper().lower().replace("hello","bye")
+(1 row)
+
+select '$.ltrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.ltrim()
+(1 row)
+
+select '$.ltrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.ltrim("xyz")
+(1 row)
+
+select '$.rtrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.rtrim()
+(1 row)
+
+select '$.rtrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.rtrim("xyz")
+(1 row)
+
+select '$.btrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.btrim()
+(1 row)
+
+select '$.btrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.btrim("xyz")
+(1 row)
+
+select '$.initcap()'::jsonpath;
+  jsonpath   
+-------------
+ $.initcap()
+(1 row)
+
+select '$.split_part("~@~", 2)'::jsonpath;
+       jsonpath        
+-----------------------
+ $.split_part("~@~",2)
+(1 row)
+
 select '$.time()'::jsonpath;
  jsonpath 
 ----------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a5269..e229e0a0d04 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -623,6 +623,114 @@ select jsonb_path_query('"2023-08-15 12:34:56 +5:30"', '$.timestamp_tz().string(
 select jsonb_path_query('"2023-08-15 12:34:56"', '$.timestamp().string()');
 rollback;
 
+-- test .ltrim()
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+select jsonb_path_query('"   hello   "', '$.ltrim()');
+select jsonb_path_query('"   hello   "', '$.ltrim()');
+select jsonb_path_query('null', '$.ltrim()');
+select jsonb_path_query('null', '$.ltrim()', silent => true);
+select jsonb_path_query('[]', '$.ltrim()');
+select jsonb_path_query('[]', 'strict $.ltrim()');
+select jsonb_path_query('{}', '$.ltrim()');
+select jsonb_path_query('[]', 'strict $.ltrim()', silent => true);
+select jsonb_path_query('{}', '$.ltrim()', silent => true);
+select jsonb_path_query('1.23', '$.ltrim()');
+select jsonb_path_query('"1.23"', '$.ltrim()');
+select jsonb_path_query('"1.23aaa"', '$.ltrim()');
+select jsonb_path_query('1234', '$.ltrim()');
+select jsonb_path_query('true', '$.ltrim()');
+select jsonb_path_query('1234', '$.ltrim().type()');
+select jsonb_path_query('[2, true]', '$.ltrim()');
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim()');
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim().type()');
+
+-- test .rtrim()
+select jsonb_path_query('"   hello   "', '$.rtrim(" ")');
+select jsonb_path_query('"   hello   "', '$.rtrim(" ")');
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+
+-- test .btrim()
+select jsonb_path_query('"   hello   "', '$.btrim(" ")');
+select jsonb_path_query('"   hello   "', '$.btrim(" ")');
+select jsonb_path_query('"   hello   "', '$.btrim()');
+select jsonb_path_query('"   hello   "', '$.btrim()');
+
+-- test .lower()
+select jsonb_path_query('null', '$.lower()');
+select jsonb_path_query('null', '$.lower()', silent => true);
+select jsonb_path_query('[]', '$.lower()');
+select jsonb_path_query('[]', 'strict $.lower()');
+select jsonb_path_query('{}', '$.lower()');
+select jsonb_path_query('[]', 'strict $.lower()', silent => true);
+select jsonb_path_query('{}', '$.lower()', silent => true);
+select jsonb_path_query('1.23', '$.lower()');
+select jsonb_path_query('"1.23"', '$.lower()');
+select jsonb_path_query('"1.23aaa"', '$.lower()');
+select jsonb_path_query('1234', '$.lower()');
+select jsonb_path_query('true', '$.lower()');
+select jsonb_path_query('1234', '$.lower().type()');
+select jsonb_path_query('[2, true]', '$.lower()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower().type()');
+
+-- test .upper()
+select jsonb_path_query('null', '$.upper()');
+select jsonb_path_query('null', '$.upper()', silent => true);
+select jsonb_path_query('[]', '$.upper()');
+select jsonb_path_query('[]', 'strict $.upper()');
+select jsonb_path_query('{}', '$.upper()');
+select jsonb_path_query('[]', 'strict $.upper()', silent => true);
+select jsonb_path_query('{}', '$.upper()', silent => true);
+select jsonb_path_query('1.23', '$.upper()');
+select jsonb_path_query('"1.23"', '$.upper()');
+select jsonb_path_query('"1.23aaa"', '$.upper()');
+select jsonb_path_query('1234', '$.upper()');
+select jsonb_path_query('true', '$.upper()');
+select jsonb_path_query('1234', '$.upper().type()');
+select jsonb_path_query('[2, true]', '$.upper()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper().type()');
+
+-- test .initcap()
+select jsonb_path_query('null', '$.initcap()');
+select jsonb_path_query('null', '$.initcap()', silent => true);
+select jsonb_path_query('[]', '$.initcap()');
+select jsonb_path_query('[]', 'strict $.initcap()');
+select jsonb_path_query('{}', '$.initcap()');
+select jsonb_path_query('[]', 'strict $.initcap()', silent => true);
+select jsonb_path_query('{}', '$.initcap()', silent => true);
+select jsonb_path_query('1.23', '$.initcap()');
+select jsonb_path_query('"1.23"', '$.initcap()');
+select jsonb_path_query('"1.23aaa"', '$.initcap()');
+select jsonb_path_query('1234', '$.initcap()');
+select jsonb_path_query('true', '$.initcap()');
+select jsonb_path_query('1234', '$.initcap().type()');
+select jsonb_path_query('[2, true]', '$.initcap()');
+select jsonb_path_query('["maybe yes", "probably no"]', '$.initcap()');
+
+-- Test .replace()
+select jsonb_path_query('null', '$.replace("x", "bye")');
+select jsonb_path_query('null', '$.replace("x", "bye")', silent => true);
+select jsonb_path_query('["x", "y", "z"]', '$.replace("x", "bye")');
+select jsonb_path_query('{}', '$.replace("x", "bye")');
+select jsonb_path_query('[]', 'strict $.replace("x", "bye")', silent => true);
+select jsonb_path_query('{}', '$.replace("x", "bye")', silent => true);
+select jsonb_path_query('1.23', '$.replace("x", "bye")');
+select jsonb_path_query('"hello world"', '$.replace("hello","bye")');
+select jsonb_path_query('"hello world"', '$.replace("hello","bye") starts with "bye"');
+
+-- Test .split_part()
+select jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)');
+
+-- Test string methods play nicely together
+select jsonb_path_query('"hello world"', '$.replace("hello","bye").upper()');
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye")');
+select jsonb_path_query('"hElLo WorlD"', '$.upper().lower().upper().replace("HELLO", "BYE")');
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye") starts with "bye"');
+select jsonb_path_query('"   hElLo WorlD "', '$.btrim().lower().upper().lower().replace("hello","bye") starts with "bye"');
+
 -- Test .time()
 select jsonb_path_query('null', '$.time()');
 select jsonb_path_query('true', '$.time()');
diff --git a/src/test/regress/sql/jsonpath.sql b/src/test/regress/sql/jsonpath.sql
index 61a5270d4e8..8752ffcf08c 100644
--- a/src/test/regress/sql/jsonpath.sql
+++ b/src/test/regress/sql/jsonpath.sql
@@ -78,6 +78,19 @@ select '$.boolean()'::jsonpath;
 select '$.date()'::jsonpath;
 select '$.decimal(4,2)'::jsonpath;
 select '$.string()'::jsonpath;
+select '$.replace("hello","bye")'::jsonpath;
+select '$.lower()'::jsonpath;
+select '$.upper()'::jsonpath;
+select '$.lower().upper().lower().replace("hello","bye")'::jsonpath;
+select '$.ltrim()'::jsonpath;
+select '$.ltrim("xyz")'::jsonpath;
+select '$.rtrim()'::jsonpath;
+select '$.rtrim("xyz")'::jsonpath;
+select '$.btrim()'::jsonpath;
+select '$.btrim("xyz")'::jsonpath;
+select '$.initcap()'::jsonpath;
+select '$.split_part("~@~", 2)'::jsonpath;
+
 select '$.time()'::jsonpath;
 select '$.time(6)'::jsonpath;
 select '$.time_tz()'::jsonpath;
-- 
2.49.0

From 86704d1c079b205ccdcb79da974a690d4dca2ad3 Mon Sep 17 00:00:00 2001
From: "David E. Wheeler" <david@justatheory.com>
Date: Mon, 2 Jun 2025 17:14:10 -0400
Subject: [PATCH v6 1/2] Rename jsonpath method arg tokens

Rename the `csv_` tokens to `int_`, because they represent signed or
unsigned integers, as follows:

*   `csv_elem` => `int_elem`
*   `csv_list` => `int_list`
*   `opt_csv_list` => `opt_int_list`

Rename the `datetime_precision` tokens to `uint_arg`, as they represent
unsigned integers and will be useful for other methods in the future, as
follows:

*   `datetime_precision` => `uint_elem`
*   `opt_datetime_precision` => `opt_uint_arg`

Rename the `datetime_template` tokens to `str_arg`, as they represent
strings and will be useful for other methods in the future, as follows:

*   `datetime_template` => `str_elem`
*   `opt_datetime_template` => `opt_str_arg`
---
 src/backend/utils/adt/jsonpath_gram.y | 42 +++++++++++++--------------
 1 file changed, 21 insertions(+), 21 deletions(-)

diff --git a/src/backend/utils/adt/jsonpath_gram.y b/src/backend/utils/adt/jsonpath_gram.y
index 499745a8fef..0b16cec18c4 100644
--- a/src/backend/utils/adt/jsonpath_gram.y
+++ b/src/backend/utils/adt/jsonpath_gram.y
@@ -92,10 +92,10 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 %type	<value>		scalar_value path_primary expr array_accessor
 					any_path accessor_op key predicate delimited_predicate
 					index_elem starts_with_initial expr_or_predicate
-					datetime_template opt_datetime_template csv_elem
-					datetime_precision opt_datetime_precision
+					str_elem opt_str_arg int_elem
+					uint_elem opt_uint_arg
 
-%type	<elems>		accessor_expr csv_list opt_csv_list
+%type	<elems>		accessor_expr int_list opt_int_list
 
 %type	<indexs>	index_list
 
@@ -254,7 +254,7 @@ accessor_op:
 	| '.' any_path					{ $$ = $2; }
 	| '.' method '(' ')'			{ $$ = makeItemType($2); }
 	| '?' '(' predicate ')'			{ $$ = makeItemUnary(jpiFilter, $3); }
-	| '.' DECIMAL_P '(' opt_csv_list ')'
+	| '.' DECIMAL_P '(' opt_int_list ')'
 		{
 			if (list_length($4) == 0)
 				$$ = makeItemBinary(jpiDecimal, NULL, NULL);
@@ -268,19 +268,19 @@ accessor_op:
 						 errmsg("invalid input syntax for type %s", "jsonpath"),
 						 errdetail(".decimal() can only have an optional precision[,scale].")));
 		}
-	| '.' DATETIME_P '(' opt_datetime_template ')'
+	| '.' DATETIME_P '(' opt_str_arg ')'
 		{ $$ = makeItemUnary(jpiDatetime, $4); }
-	| '.' TIME_P '(' opt_datetime_precision ')'
+	| '.' TIME_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTime, $4); }
-	| '.' TIME_TZ_P '(' opt_datetime_precision ')'
+	| '.' TIME_TZ_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimeTz, $4); }
-	| '.' TIMESTAMP_P '(' opt_datetime_precision ')'
+	| '.' TIMESTAMP_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimestamp, $4); }
-	| '.' TIMESTAMP_TZ_P '(' opt_datetime_precision ')'
+	| '.' TIMESTAMP_TZ_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimestampTz, $4); }
 	;
 
-csv_elem:
+int_elem:
 	INT_P
 		{ $$ = makeItemNumeric(&$1); }
 	| '+' INT_P %prec UMINUS
@@ -289,31 +289,31 @@ csv_elem:
 		{ $$ = makeItemUnary(jpiMinus, makeItemNumeric(&$2)); }
 	;
 
-csv_list:
-	csv_elem						{ $$ = list_make1($1); }
-	| csv_list ',' csv_elem			{ $$ = lappend($1, $3); }
+int_list:
+	int_elem						{ $$ = list_make1($1); }
+	| int_list ',' int_elem			{ $$ = lappend($1, $3); }
 	;
 
-opt_csv_list:
-	csv_list						{ $$ = $1; }
+opt_int_list:
+	int_list						{ $$ = $1; }
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
-datetime_precision:
+uint_elem:
 	INT_P							{ $$ = makeItemNumeric(&$1); }
 	;
 
-opt_datetime_precision:
-	datetime_precision				{ $$ = $1; }
+opt_uint_arg:
+	uint_elem						{ $$ = $1; }
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
-datetime_template:
+str_elem:
 	STRING_P						{ $$ = makeItemString(&$1); }
 	;
 
-opt_datetime_template:
-	datetime_template				{ $$ = $1; }
+opt_str_arg:
+	str_elem						{ $$ = $1; }
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
-- 
2.49.0

From fc273e5445a38ff77ecdb77757dc2ff4fba42091 Mon Sep 17 00:00:00 2001
From: Florents Tselai <florents.tselai@gmail.com>
Date: Tue, 3 Jun 2025 14:58:36 -0400
Subject: [PATCH v6 2/2] Add additional jsonpath string methods

Add the following jsonpath methods:

*   l/r/btrim()
*   lower(), upper()
*   initcap()
*   replace()
*   split_part()

Each simply dispatches to the standard string processing functions.
These depend on the locale, but since it's set at `initdb`, they can be
considered immutable and therefore allowed in any jsonpath expression.
---
 doc/src/sgml/func.sgml                       | 140 +++++++
 src/backend/utils/adt/jsonpath.c             | 126 +++++-
 src/backend/utils/adt/jsonpath_exec.c        | 200 ++++++++++
 src/backend/utils/adt/jsonpath_gram.y        |  29 +-
 src/backend/utils/adt/jsonpath_scan.l        |   8 +
 src/include/utils/jsonpath.h                 |   8 +
 src/test/regress/expected/jsonb_jsonpath.out | 399 +++++++++++++++++++
 src/test/regress/expected/jsonpath.out       | 137 +++++++
 src/test/regress/sql/jsonb_jsonpath.sql      | 109 +++++
 src/test/regress/sql/jsonpath.sql            |  31 ++
 10 files changed, 1183 insertions(+), 4 deletions(-)

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index c67688cbf5f..674c22c78d8 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -18627,6 +18627,146 @@ ERROR:  jsonpath member accessor can only be applied to an object
         <returnvalue>[{"id": 0, "key": "x", "value": "20"}, {"id": 0, "key": "y", "value": 32}]</returnvalue>
        </para></entry>
       </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>lower()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String converted to all lower case according to the rules of the database's locale.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"TOM"', '$.lower()')</literal>
+        <returnvalue>"tom"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>upper()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String converted to all upper case according to the rules of the database's locale.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"tom"', '$.upper()')</literal>
+        <returnvalue>"TOM"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>initcap()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the first letter of each word converted to upper case
+        according to the rules of the database's locale. Words are sequences
+        of alphanumeric characters separated by non-alphanumeric characters.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"hi THOMAS"', '$.initcap()')</literal>
+        <returnvalue>"Hi Thomas"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>replace(<replaceable>from</replaceable>, <replaceable>to</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with all occurrences of substring from replaced with substring to.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"abcdefabcdef"', '$.replace("cd", "XX")')</literal>
+        <returnvalue>"abXXefabXXef"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>split_part(<replaceable>delimiter</replaceable>, <replaceable>n</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String split at occurrences of <replaceable>delimiter</replaceable>
+        and returns the <replaceable>n</replaceable>'th field (counting from
+        one) or, when <replaceable>n</replaceable> is negative, returns the
+        |<replaceable>n</replaceable>|'th-from-last field.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)')</literal>
+        <returnvalue>"def"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"abc,def,ghi,jkl"', '$.split_part(",", 2)')</literal>
+        <returnvalue>"ghi"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>ltrim(<replaceable>characters</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the longest string containing only spaces or the
+        characters in <replaceable>characters</replaceable> removed from the
+        start of <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal> jsonb_path_query('"  hello"', '$.ltrim()')</literal>
+        <returnvalue>"hello"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"zzzytest"', '$.ltrim("xyz")')</literal>
+        <returnvalue>"test"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>rtrim([ <replaceable>characters</replaceable> ])</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the longest string containing only spaces or the
+        characters in <replaceable>characters</replaceable> removed from the
+        end of <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"hello  "', '$.rtrim()')</literal>
+        <returnvalue>"hello"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"testxxzx"', '$.rtrim("xyz")')</literal>
+        <returnvalue>"test"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>btrim([ <replaceable>characters</replaceable> ])</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the longest string containing only spaces or the
+        characters in <replaceable>characters</replaceable> removed from the
+        start and end of <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"  hello  "', '$.btrim()')</literal>
+        <returnvalue>"hello"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"xyxtrimyyx"', '$.btrim("xyz")')</literal>
+        <returnvalue>"trim"</returnvalue>
+       </para></entry>
+      </row>
+
      </tbody>
     </tgroup>
    </table>
diff --git a/src/backend/utils/adt/jsonpath.c b/src/backend/utils/adt/jsonpath.c
index 762f7e8a09d..524f0f8daec 100644
--- a/src/backend/utils/adt/jsonpath.c
+++ b/src/backend/utils/adt/jsonpath.c
@@ -298,6 +298,8 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 		case jpiMod:
 		case jpiStartsWith:
 		case jpiDecimal:
+		case jpiStrReplace:
+		case jpiStrSplitPart:
 			{
 				/*
 				 * First, reserve place for left/right arg's positions, then
@@ -362,6 +364,9 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 		case jpiTimeTz:
 		case jpiTimestamp:
 		case jpiTimestampTz:
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
 			{
 				int32		arg = reserveSpaceForItemPointer(buf);
 
@@ -457,6 +462,9 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 		case jpiInteger:
 		case jpiNumber:
 		case jpiStringFunc:
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrInitcap:
 			break;
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", item->type);
@@ -831,6 +839,72 @@ printJsonPathItem(StringInfo buf, JsonPathItem *v, bool inKey,
 			}
 			appendStringInfoChar(buf, ')');
 			break;
+		case jpiStrReplace:
+			appendStringInfoString(buf, ".replace(");
+			if (v->content.args.left)
+			{
+				jspGetLeftArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			if (v->content.args.right)
+			{
+				appendStringInfoChar(buf, ',');
+				jspGetRightArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrSplitPart:
+			appendStringInfoString(buf, ".split_part(");
+			if (v->content.args.left)
+			{
+				jspGetLeftArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			if (v->content.args.right)
+			{
+				appendStringInfoChar(buf, ',');
+				jspGetRightArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrLower:
+			appendStringInfoString(buf, ".lower()");
+			break;
+		case jpiStrUpper:
+			appendStringInfoString(buf, ".upper()");
+			break;
+		case jpiStrInitcap:
+			appendStringInfoString(buf, ".initcap()");
+			break;
+		case jpiStrLtrim:
+			appendStringInfoString(buf, ".ltrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrRtrim:
+			appendStringInfoString(buf, ".rtrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrBtrim:
+			appendStringInfoString(buf, ".btrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", v->type);
 	}
@@ -906,6 +980,12 @@ jspOperationName(JsonPathItemType type)
 			return "number";
 		case jpiStringFunc:
 			return "string";
+		case jpiStrReplace:
+			return "replace";
+		case jpiStrLower:
+			return "lower";
+		case jpiStrUpper:
+			return "upper";
 		case jpiTime:
 			return "time";
 		case jpiTimeTz:
@@ -914,6 +994,16 @@ jspOperationName(JsonPathItemType type)
 			return "timestamp";
 		case jpiTimestampTz:
 			return "timestamp_tz";
+		case jpiStrLtrim:
+			return "ltrim";
+		case jpiStrRtrim:
+			return "rtrim";
+		case jpiStrBtrim:
+			return "btrim";
+		case jpiStrInitcap:
+			return "initcap";
+		case jpiStrSplitPart:
+			return "split_part";
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", type);
 			return NULL;
@@ -1016,6 +1106,9 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 		case jpiInteger:
 		case jpiNumber:
 		case jpiStringFunc:
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrInitcap:
 			break;
 		case jpiString:
 		case jpiKey:
@@ -1041,6 +1134,8 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 		case jpiMod:
 		case jpiStartsWith:
 		case jpiDecimal:
+		case jpiStrReplace:
+		case jpiStrSplitPart:
 			read_int32(v->content.args.left, base, pos);
 			read_int32(v->content.args.right, base, pos);
 			break;
@@ -1055,6 +1150,9 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 		case jpiTimeTz:
 		case jpiTimestamp:
 		case jpiTimestampTz:
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
 			read_int32(v->content.arg, base, pos);
 			break;
 		case jpiIndexArray:
@@ -1090,7 +1188,10 @@ jspGetArg(JsonPathItem *v, JsonPathItem *a)
 		   v->type == jpiTime ||
 		   v->type == jpiTimeTz ||
 		   v->type == jpiTimestamp ||
-		   v->type == jpiTimestampTz);
+		   v->type == jpiTimestampTz ||
+		   v->type == jpiStrLtrim ||
+		   v->type == jpiStrRtrim ||
+		   v->type == jpiStrBtrim);
 
 	jspInitByBuffer(a, v->base, v->content.arg);
 }
@@ -1149,10 +1250,18 @@ jspGetNext(JsonPathItem *v, JsonPathItem *a)
 			   v->type == jpiInteger ||
 			   v->type == jpiNumber ||
 			   v->type == jpiStringFunc ||
+			   v->type == jpiStrReplace ||
+			   v->type == jpiStrLower ||
+			   v->type == jpiStrUpper ||
 			   v->type == jpiTime ||
 			   v->type == jpiTimeTz ||
 			   v->type == jpiTimestamp ||
-			   v->type == jpiTimestampTz);
+			   v->type == jpiTimestampTz ||
+			   v->type == jpiStrLtrim ||
+			   v->type == jpiStrRtrim ||
+			   v->type == jpiStrBtrim ||
+			   v->type == jpiStrInitcap ||
+			   v->type == jpiStrSplitPart);
 
 		if (a)
 			jspInitByBuffer(a, v->base, v->nextPos);
@@ -1201,11 +1310,14 @@ jspGetRightArg(JsonPathItem *v, JsonPathItem *a)
 		   v->type == jpiDiv ||
 		   v->type == jpiMod ||
 		   v->type == jpiStartsWith ||
-		   v->type == jpiDecimal);
+		   v->type == jpiDecimal ||
+		   v->type == jpiStrReplace ||
+		   v->type == jpiStrSplitPart);
 
 	jspInitByBuffer(a, v->base, v->content.args.right);
 }
 
+
 bool
 jspGetBool(JsonPathItem *v)
 {
@@ -1501,6 +1613,14 @@ jspIsMutableWalker(JsonPathItem *jpi, struct JsonPathMutableContext *cxt)
 			case jpiInteger:
 			case jpiNumber:
 			case jpiStringFunc:
+			case jpiStrReplace:
+			case jpiStrLower:
+			case jpiStrUpper:
+			case jpiStrLtrim:
+			case jpiStrRtrim:
+			case jpiStrBtrim:
+			case jpiStrInitcap:
+			case jpiStrSplitPart:
 				status = jpdsNonDateTime;
 				break;
 
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index dbab24737ef..2095f2a9c21 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -301,6 +301,8 @@ static JsonPathExecResult executeNumericItemMethod(JsonPathExecContext *cxt,
 												   JsonValueList *found);
 static JsonPathExecResult executeDateTimeMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
 												JsonbValue *jb, JsonValueList *found);
+static JsonPathExecResult executeStringInternalMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
+												JsonbValue *jb, JsonValueList *found);
 static JsonPathExecResult executeKeyValueMethod(JsonPathExecContext *cxt,
 												JsonPathItem *jsp, JsonbValue *jb, JsonValueList *found);
 static JsonPathExecResult appendBoolResult(JsonPathExecContext *cxt,
@@ -1659,6 +1661,23 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
 			}
 			break;
 
+		case jpiStrLtrim:
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrReplace:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
+		case jpiStrInitcap:
+		case jpiStrSplitPart:
+		{
+			if (unwrap && JsonbType(jb) == jbvArray)
+				return executeItemUnwrapTargetArray(cxt, jsp, jb, found, false);
+
+			return executeStringInternalMethod(cxt, jsp, jb, found);
+		}
+		break;
+
+
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", jsp->type);
 	}
@@ -2792,6 +2811,187 @@ executeDateTimeMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
 	return executeNextItem(cxt, jsp, &elem, jb, found, hasNext);
 }
 
+/*
+ * Implementation of .upper(), lower() et. al. methods,
+ * that forward their actual implementation to internal functions.
+ */
+static JsonPathExecResult executeStringInternalMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
+												JsonbValue *jb, JsonValueList *found) {
+	Assert(	jsp->type == jpiStrLower ||
+			jsp->type == jpiStrUpper ||
+			jsp->type == jpiStrReplace ||
+			jsp->type == jpiStrLtrim ||
+			jsp->type == jpiStrRtrim ||
+			jsp->type == jpiStrBtrim ||
+			jsp->type == jpiStrInitcap ||
+			jsp->type == jpiStrSplitPart);
+	JsonbValue	jbvbuf;
+	bool		hasNext;
+	JsonPathExecResult res = jperNotFound;
+	JsonPathItem elem;
+	Datum		str; /* Datum representation for the current string value. The first argument to internal functions */
+	char		*tmp = NULL;
+	char		*resStr = NULL;
+
+	if (!(jb = getScalar(jb, jbvString)))
+		RETURN_ERROR(ereport(ERROR,
+							 (errcode(ERRCODE_INVALID_ARGUMENT_FOR_SQL_JSON_DATETIME_FUNCTION),
+							  errmsg("jsonpath item method .%s() can only be applied to a string",
+									 jspOperationName(jsp->type)))));
+
+	tmp = pnstrdup(jb->val.string.val, jb->val.string.len);
+	str = CStringGetTextDatum(tmp);
+
+	/* Internal string functions that accept no arguments */
+	switch (jsp->type)
+	{
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
+		{
+			char	   *characters_str;
+			int			characters_len;
+			PGFunction	func = NULL;
+
+			if (jsp->content.arg)
+			{
+				switch (jsp->type)
+				{
+					case jpiStrLtrim:
+						func = ltrim;
+						break;
+					case jpiStrRtrim:
+						func = rtrim;
+						break;
+					case jpiStrBtrim:
+						func = btrim;
+						break;
+					default: ;
+				}
+				jspGetArg(jsp, &elem);
+				if (elem.type != jpiString)
+					elog(ERROR, "invalid jsonpath item type for .%s() argument", jspOperationName(jsp->type));
+
+				characters_str = jspGetString(&elem, &characters_len);
+				resStr = TextDatumGetCString(DirectFunctionCall2Coll(func,
+					DEFAULT_COLLATION_OID, str,
+					CStringGetTextDatum(characters_str)));
+				break;
+			}
+
+			switch (jsp->type)
+			{
+				case jpiStrLtrim:
+					func = ltrim1;
+					break;
+				case jpiStrRtrim:
+					func = rtrim1;
+					break;
+				case jpiStrBtrim:
+					func = btrim1;
+					break;
+				default: ;
+			}
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(func,
+					DEFAULT_COLLATION_OID, str));
+			break;
+		}
+
+		case jpiStrLower:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(lower, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiStrUpper:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(upper, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiStrInitcap:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(initcap, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiStrReplace:
+		{
+			char		*from_str, *to_str;
+			int			from_len, to_len;
+
+			jspGetLeftArg(jsp, &elem);
+			if (elem.type != jpiString)
+				elog(ERROR, "invalid jsonpath item type for .replace() from");
+
+			from_str = jspGetString(&elem, &from_len);
+
+			jspGetRightArg(jsp, &elem);
+			if (elem.type != jpiString)
+				elog(ERROR, "invalid jsonpath item type for .replace() to");
+
+			to_str = jspGetString(&elem, &to_len);
+
+			resStr = TextDatumGetCString(DirectFunctionCall3Coll(replace_text,
+				C_COLLATION_OID,
+				CStringGetTextDatum(tmp),
+				CStringGetTextDatum(from_str),
+				CStringGetTextDatum(to_str)));
+			break;
+		}
+		case jpiStrSplitPart:
+		{
+			char		*from_str;
+			Numeric		n;
+			int			from_len;
+
+			jspGetLeftArg(jsp, &elem);
+			if (elem.type != jpiString)
+				elog(ERROR, "invalid jsonpath item type for .split_part()");
+
+			from_str = jspGetString(&elem, &from_len);
+
+			jspGetRightArg(jsp, &elem);
+			if (elem.type != jpiNumeric)
+				elog(ERROR, "invalid jsonpath item type for .split_part()");
+
+			n = jspGetNumeric(&elem);
+
+			resStr = TextDatumGetCString(DirectFunctionCall3Coll(split_part,
+				C_COLLATION_OID,
+				CStringGetTextDatum(tmp),
+				CStringGetTextDatum(from_str),
+				DirectFunctionCall1(numeric_int8, NumericGetDatum(n))));
+			break;
+		}
+		default:
+			elog(ERROR, "unsupported jsonpath item type: %d", jsp->type);
+	}
+
+	if (resStr)
+		res = jperOk;
+
+	hasNext = jspGetNext(jsp, &elem);
+
+	if (!hasNext && !found)
+		return res;
+
+	jb = hasNext ? &jbvbuf : palloc(sizeof(*jb));
+
+	/* Create the appropriate jb value to return */
+	switch (jsp->type)
+	{
+		/* Cases for functions that return text */
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrReplace:
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
+		case jpiStrInitcap:
+		case jpiStrSplitPart:
+			jb->type = jbvString;
+			jb->val.string.val = resStr;
+			jb->val.string.len = strlen(jb->val.string.val);
+		default:
+			;
+			/* cant' happen */
+	}
+
+	return executeNextItem(cxt, jsp, &elem, jb, found, hasNext);
+}
+
 /*
  * Implementation of .keyvalue() method.
  *
diff --git a/src/backend/utils/adt/jsonpath_gram.y b/src/backend/utils/adt/jsonpath_gram.y
index 0b16cec18c4..a48d80f560f 100644
--- a/src/backend/utils/adt/jsonpath_gram.y
+++ b/src/backend/utils/adt/jsonpath_gram.y
@@ -44,6 +44,7 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 							  JsonPathParseItem ** result,
 							  struct Node *escontext);
 
+
 /*
  * Bison doesn't allocate anything that needs to live across parser calls,
  * so we can easily have it use palloc instead of malloc.  This prevents
@@ -86,6 +87,8 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 %token	<str>		DATETIME_P
 %token	<str>		BIGINT_P BOOLEAN_P DATE_P DECIMAL_P INTEGER_P NUMBER_P
 %token	<str>		STRINGFUNC_P TIME_P TIME_TZ_P TIMESTAMP_P TIMESTAMP_TZ_P
+%token	<str>		STR_REPLACE_P STR_LOWER_P STR_UPPER_P STR_LTRIM_P STR_RTRIM_P STR_BTRIM_P
+					STR_INITCAP_P STR_SPLIT_PART_P
 
 %type	<result>	result
 
@@ -95,7 +98,7 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 					str_elem opt_str_arg int_elem
 					uint_elem opt_uint_arg
 
-%type	<elems>		accessor_expr int_list opt_int_list
+%type	<elems>		accessor_expr int_list opt_int_list str_int_args str_str_args
 
 %type	<indexs>	index_list
 
@@ -278,6 +281,16 @@ accessor_op:
 		{ $$ = makeItemUnary(jpiTimestamp, $4); }
 	| '.' TIMESTAMP_TZ_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimestampTz, $4); }
+	| '.' STR_REPLACE_P '(' str_str_args ')'
+		{ $$ = makeItemBinary(jpiStrReplace, linitial($4), lsecond($4)); }
+	| '.' STR_SPLIT_PART_P '(' str_int_args ')'
+		{ $$ = makeItemBinary(jpiStrSplitPart, linitial($4), lsecond($4)); }
+	| '.' STR_LTRIM_P '(' opt_str_arg ')'
+		{ $$ = makeItemUnary(jpiStrLtrim, $4); }
+	| '.' STR_RTRIM_P '(' opt_str_arg ')'
+		{ $$ = makeItemUnary(jpiStrRtrim, $4); }
+	| '.' STR_BTRIM_P '(' opt_str_arg ')'
+		{ $$ = makeItemUnary(jpiStrBtrim, $4); }
 	;
 
 int_elem:
@@ -317,6 +330,14 @@ opt_str_arg:
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
+str_int_args:
+	str_elem ',' int_elem			{ $$ = list_make2($1, $3) }
+	;
+
+str_str_args:
+	str_elem ',' str_elem 			{ $$ = list_make2($1, $3) }
+	;
+
 key:
 	key_name						{ $$ = makeItemKey(&$1); }
 	;
@@ -357,6 +378,9 @@ key_name:
 	| TIME_TZ_P
 	| TIMESTAMP_P
 	| TIMESTAMP_TZ_P
+	| STR_LTRIM_P
+	| STR_RTRIM_P
+	| STR_BTRIM_P
 	;
 
 method:
@@ -373,6 +397,9 @@ method:
 	| INTEGER_P						{ $$ = jpiInteger; }
 	| NUMBER_P						{ $$ = jpiNumber; }
 	| STRINGFUNC_P					{ $$ = jpiStringFunc; }
+	| STR_LOWER_P					{ $$ = jpiStrLower; }
+	| STR_UPPER_P					{ $$ = jpiStrUpper; }
+	| STR_INITCAP_P					{ $$ = jpiStrInitcap; }
 	;
 %%
 
diff --git a/src/backend/utils/adt/jsonpath_scan.l b/src/backend/utils/adt/jsonpath_scan.l
index c7aab83eeb4..69c61f98500 100644
--- a/src/backend/utils/adt/jsonpath_scan.l
+++ b/src/backend/utils/adt/jsonpath_scan.l
@@ -413,8 +413,13 @@ static const JsonPathKeyword keywords[] = {
 	{4, true, TRUE_P, "true"},
 	{4, false, TYPE_P, "type"},
 	{4, false, WITH_P, "with"},
+	{5, false, STR_BTRIM_P, "btrim"},
 	{5, true, FALSE_P, "false"},
 	{5, false, FLOOR_P, "floor"},
+	{5, false, STR_LOWER_P, "lower"},
+	{5, false, STR_LTRIM_P, "ltrim"},
+	{5, false, STR_RTRIM_P, "rtrim"},
+	{5, false, STR_UPPER_P, "upper"},
 	{6, false, BIGINT_P, "bigint"},
 	{6, false, DOUBLE_P, "double"},
 	{6, false, EXISTS_P, "exists"},
@@ -425,13 +430,16 @@ static const JsonPathKeyword keywords[] = {
 	{7, false, BOOLEAN_P, "boolean"},
 	{7, false, CEILING_P, "ceiling"},
 	{7, false, DECIMAL_P, "decimal"},
+	{7, false, STR_INITCAP_P, "initcap"},
 	{7, false, INTEGER_P, "integer"},
+	{7, false, STR_REPLACE_P, "replace"},
 	{7, false, TIME_TZ_P, "time_tz"},
 	{7, false, UNKNOWN_P, "unknown"},
 	{8, false, DATETIME_P, "datetime"},
 	{8, false, KEYVALUE_P, "keyvalue"},
 	{9, false, TIMESTAMP_P, "timestamp"},
 	{10, false, LIKE_REGEX_P, "like_regex"},
+	{10,false, STR_SPLIT_PART_P, "split_part"},
 	{12, false, TIMESTAMP_TZ_P, "timestamp_tz"},
 };
 
diff --git a/src/include/utils/jsonpath.h b/src/include/utils/jsonpath.h
index 23a76d233e9..2d0c53f7b06 100644
--- a/src/include/utils/jsonpath.h
+++ b/src/include/utils/jsonpath.h
@@ -115,6 +115,14 @@ typedef enum JsonPathItemType
 	jpiTimeTz,					/* .time_tz() item method */
 	jpiTimestamp,				/* .timestamp() item method */
 	jpiTimestampTz,				/* .timestamp_tz() item method */
+	jpiStrReplace,				/* .replace() item method */
+	jpiStrLower,				/* .lower() item method */
+	jpiStrUpper,				/* .upper() item method */
+	jpiStrLtrim,				/* .ltrim() item method */
+	jpiStrRtrim,				/* .rtrim() item method */
+	jpiStrBtrim,				/* .btrim() item method */
+	jpiStrInitcap,				/* .initcap() item method */
+	jpiStrSplitPart,			/* .split_part() item method */
 } JsonPathItemType;
 
 /* XQuery regex mode flags for LIKE_REGEX predicate */
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e91a29..cea539717f9 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -2723,6 +2723,405 @@ select jsonb_path_query('"2023-08-15 12:34:56"', '$.timestamp().string()');
 (1 row)
 
 rollback;
+-- test .ltrim()
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"zzzytest"', '$.ltrim("xyz")');
+ jsonb_path_query 
+------------------
+ "test"
+(1 row)
+
+select jsonb_path_query('null', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('null', '$.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.ltrim()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('{}', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('true', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('1234', '$.ltrim().type()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim()');
+  jsonb_path_query_array  
+--------------------------
+ ["maybe  ", "yes", "no"]
+(1 row)
+
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .rtrim()
+select jsonb_path_query('"   hello   "', '$.rtrim(" ")');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+select jsonb_path_query('"testxxzx"', '$.rtrim("xyz")');
+ jsonb_path_query 
+------------------
+ "test"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+-- test .btrim()
+select jsonb_path_query('"   hello   "', '$.btrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+select jsonb_path_query('"xyxtrimyyx"', '$.btrim("xyz")');
+ jsonb_path_query 
+------------------
+ "trim"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.btrim()');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.btrim()');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+-- test .lower()
+select jsonb_path_query('null', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('null', '$.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.lower()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('{}', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.lower()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.lower()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('true', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('1234', '$.lower().type()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower()');
+ jsonb_path_query_array 
+------------------------
+ ["maybe", "yes", "no"]
+(1 row)
+
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .upper()
+select jsonb_path_query('null', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('null', '$.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.upper()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('{}', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.upper()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.upper()');
+ jsonb_path_query 
+------------------
+ "1.23AAA"
+(1 row)
+
+select jsonb_path_query('1234', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('true', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('1234', '$.upper().type()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper()');
+ jsonb_path_query_array 
+------------------------
+ ["MAYBE", "YES", "NO"]
+(1 row)
+
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .initcap()
+select jsonb_path_query('null', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('null', '$.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.initcap()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('{}', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('true', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('1234', '$.initcap().type()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('["maybe yes", "probably no"]', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "Maybe Yes"
+ "Probably No"
+(2 rows)
+
+-- Test .replace()
+select jsonb_path_query('null', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('null', '$.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('["x", "y", "z"]', '$.replace("x", "bye")');
+ jsonb_path_query 
+------------------
+ "bye"
+ "y"
+ "z"
+(3 rows)
+
+select jsonb_path_query('{}', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('"hello world"', '$.replace("hello","bye")');
+ jsonb_path_query 
+------------------
+ "bye world"
+(1 row)
+
+select jsonb_path_query('"hello world"', '$.replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
+-- Test .split_part()
+select jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)');
+ jsonb_path_query 
+------------------
+ "def"
+(1 row)
+
+select jsonb_path_query('"abc,def,ghi,jkl"', '$.split_part(",", -2)');
+ jsonb_path_query 
+------------------
+ "ghi"
+(1 row)
+
+-- Test string methods play nicely together
+select jsonb_path_query('"hello world"', '$.replace("hello","bye").upper()');
+ jsonb_path_query 
+------------------
+ "BYE WORLD"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye")');
+ jsonb_path_query 
+------------------
+ "bye world"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.upper().lower().upper().replace("HELLO", "BYE")');
+ jsonb_path_query 
+------------------
+ "BYE WORLD"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
+select jsonb_path_query('"   hElLo WorlD "', '$.btrim().lower().upper().lower().replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
 -- Test .time()
 select jsonb_path_query('null', '$.time()');
 ERROR:  jsonpath item method .time() can only be applied to a string
diff --git a/src/test/regress/expected/jsonpath.out b/src/test/regress/expected/jsonpath.out
index fd9bd755f52..a13022feabd 100644
--- a/src/test/regress/expected/jsonpath.out
+++ b/src/test/regress/expected/jsonpath.out
@@ -435,6 +435,143 @@ select '$.string()'::jsonpath;
  $.string()
 (1 row)
 
+select '$.replace("hello","bye")'::jsonpath;
+         jsonpath         
+--------------------------
+ $.replace("hello","bye")
+(1 row)
+
+select '$.lower()'::jsonpath;
+ jsonpath  
+-----------
+ $.lower()
+(1 row)
+
+select '$.upper()'::jsonpath;
+ jsonpath  
+-----------
+ $.upper()
+(1 row)
+
+select '$.lower().upper().lower().replace("hello","bye")'::jsonpath;
+                     jsonpath                     
+--------------------------------------------------
+ $.lower().upper().lower().replace("hello","bye")
+(1 row)
+
+select '$.ltrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.ltrim()
+(1 row)
+
+select '$.ltrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.ltrim("xyz")
+(1 row)
+
+select '$.rtrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.rtrim()
+(1 row)
+
+select '$.rtrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.rtrim("xyz")
+(1 row)
+
+select '$.btrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.btrim()
+(1 row)
+
+select '$.btrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.btrim("xyz")
+(1 row)
+
+select '$.initcap()'::jsonpath;
+  jsonpath   
+-------------
+ $.initcap()
+(1 row)
+
+select '$.split_part("~@~", 2)'::jsonpath;
+       jsonpath        
+-----------------------
+ $.split_part("~@~",2)
+(1 row)
+
+-- Parse errors
+select '$.replace("hello")'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.replace("hello")'::jsonpath;
+               ^
+select '$.replace()'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.replace()'::jsonpath;
+               ^
+select '$.replace("hello","bye","extra")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.replace("hello","bye","extra")'::jsonpath;
+               ^
+select '$.split_part("~@~")'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.split_part("~@~")'::jsonpath;
+               ^
+select '$.split_part()'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.split_part()'::jsonpath;
+               ^
+select '$.split_part("~@~", "hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.split_part("~@~", "hi")'::jsonpath;
+               ^
+select '$.split_part("~@~", 2, "extra")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.split_part("~@~", 2, "extra")'::jsonpath;
+               ^
+select '$.lower("hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.lower("hi")'::jsonpath;
+               ^
+select '$.upper("hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.upper("hi")'::jsonpath;
+               ^
+select '$.initcap("hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.initcap("hi")'::jsonpath;
+               ^
+select '$.ltrim(42)'::jsonpath;
+ERROR:  syntax error at or near "42" of jsonpath input
+LINE 1: select '$.ltrim(42)'::jsonpath;
+               ^
+select '$.ltrim("x", "y")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.ltrim("x", "y")'::jsonpath;
+               ^
+select '$.rtrim(42)'::jsonpath;
+ERROR:  syntax error at or near "42" of jsonpath input
+LINE 1: select '$.rtrim(42)'::jsonpath;
+               ^
+select '$.rtrim("x", "y")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.rtrim("x", "y")'::jsonpath;
+               ^
+select '$.trim(42)'::jsonpath;
+ERROR:  syntax error at or near "(" of jsonpath input
+LINE 1: select '$.trim(42)'::jsonpath;
+               ^
+select '$.trim("x", "y")'::jsonpath;
+ERROR:  syntax error at or near "(" of jsonpath input
+LINE 1: select '$.trim("x", "y")'::jsonpath;
+               ^
 select '$.time()'::jsonpath;
  jsonpath 
 ----------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a5269..8169719343e 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -623,6 +623,115 @@ select jsonb_path_query('"2023-08-15 12:34:56 +5:30"', '$.timestamp_tz().string(
 select jsonb_path_query('"2023-08-15 12:34:56"', '$.timestamp().string()');
 rollback;
 
+-- test .ltrim()
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+select jsonb_path_query('"   hello   "', '$.ltrim()');
+select jsonb_path_query('"zzzytest"', '$.ltrim("xyz")');
+select jsonb_path_query('null', '$.ltrim()');
+select jsonb_path_query('null', '$.ltrim()', silent => true);
+select jsonb_path_query('[]', '$.ltrim()');
+select jsonb_path_query('[]', 'strict $.ltrim()');
+select jsonb_path_query('{}', '$.ltrim()');
+select jsonb_path_query('[]', 'strict $.ltrim()', silent => true);
+select jsonb_path_query('{}', '$.ltrim()', silent => true);
+select jsonb_path_query('1.23', '$.ltrim()');
+select jsonb_path_query('"1.23"', '$.ltrim()');
+select jsonb_path_query('"1.23aaa"', '$.ltrim()');
+select jsonb_path_query('1234', '$.ltrim()');
+select jsonb_path_query('true', '$.ltrim()');
+select jsonb_path_query('1234', '$.ltrim().type()');
+select jsonb_path_query('[2, true]', '$.ltrim()');
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim()');
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim().type()');
+
+-- test .rtrim()
+select jsonb_path_query('"   hello   "', '$.rtrim(" ")');
+select jsonb_path_query('"testxxzx"', '$.rtrim("xyz")');
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+
+-- test .btrim()
+select jsonb_path_query('"   hello   "', '$.btrim(" ")');
+select jsonb_path_query('"xyxtrimyyx"', '$.btrim("xyz")');
+select jsonb_path_query('"   hello   "', '$.btrim()');
+select jsonb_path_query('"   hello   "', '$.btrim()');
+
+-- test .lower()
+select jsonb_path_query('null', '$.lower()');
+select jsonb_path_query('null', '$.lower()', silent => true);
+select jsonb_path_query('[]', '$.lower()');
+select jsonb_path_query('[]', 'strict $.lower()');
+select jsonb_path_query('{}', '$.lower()');
+select jsonb_path_query('[]', 'strict $.lower()', silent => true);
+select jsonb_path_query('{}', '$.lower()', silent => true);
+select jsonb_path_query('1.23', '$.lower()');
+select jsonb_path_query('"1.23"', '$.lower()');
+select jsonb_path_query('"1.23aaa"', '$.lower()');
+select jsonb_path_query('1234', '$.lower()');
+select jsonb_path_query('true', '$.lower()');
+select jsonb_path_query('1234', '$.lower().type()');
+select jsonb_path_query('[2, true]', '$.lower()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower().type()');
+
+-- test .upper()
+select jsonb_path_query('null', '$.upper()');
+select jsonb_path_query('null', '$.upper()', silent => true);
+select jsonb_path_query('[]', '$.upper()');
+select jsonb_path_query('[]', 'strict $.upper()');
+select jsonb_path_query('{}', '$.upper()');
+select jsonb_path_query('[]', 'strict $.upper()', silent => true);
+select jsonb_path_query('{}', '$.upper()', silent => true);
+select jsonb_path_query('1.23', '$.upper()');
+select jsonb_path_query('"1.23"', '$.upper()');
+select jsonb_path_query('"1.23aaa"', '$.upper()');
+select jsonb_path_query('1234', '$.upper()');
+select jsonb_path_query('true', '$.upper()');
+select jsonb_path_query('1234', '$.upper().type()');
+select jsonb_path_query('[2, true]', '$.upper()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper().type()');
+
+-- test .initcap()
+select jsonb_path_query('null', '$.initcap()');
+select jsonb_path_query('null', '$.initcap()', silent => true);
+select jsonb_path_query('[]', '$.initcap()');
+select jsonb_path_query('[]', 'strict $.initcap()');
+select jsonb_path_query('{}', '$.initcap()');
+select jsonb_path_query('[]', 'strict $.initcap()', silent => true);
+select jsonb_path_query('{}', '$.initcap()', silent => true);
+select jsonb_path_query('1.23', '$.initcap()');
+select jsonb_path_query('"1.23"', '$.initcap()');
+select jsonb_path_query('"1.23aaa"', '$.initcap()');
+select jsonb_path_query('1234', '$.initcap()');
+select jsonb_path_query('true', '$.initcap()');
+select jsonb_path_query('1234', '$.initcap().type()');
+select jsonb_path_query('[2, true]', '$.initcap()');
+select jsonb_path_query('["maybe yes", "probably no"]', '$.initcap()');
+
+-- Test .replace()
+select jsonb_path_query('null', '$.replace("x", "bye")');
+select jsonb_path_query('null', '$.replace("x", "bye")', silent => true);
+select jsonb_path_query('["x", "y", "z"]', '$.replace("x", "bye")');
+select jsonb_path_query('{}', '$.replace("x", "bye")');
+select jsonb_path_query('[]', 'strict $.replace("x", "bye")', silent => true);
+select jsonb_path_query('{}', '$.replace("x", "bye")', silent => true);
+select jsonb_path_query('1.23', '$.replace("x", "bye")');
+select jsonb_path_query('"hello world"', '$.replace("hello","bye")');
+select jsonb_path_query('"hello world"', '$.replace("hello","bye") starts with "bye"');
+
+-- Test .split_part()
+select jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)');
+select jsonb_path_query('"abc,def,ghi,jkl"', '$.split_part(",", -2)');
+
+-- Test string methods play nicely together
+select jsonb_path_query('"hello world"', '$.replace("hello","bye").upper()');
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye")');
+select jsonb_path_query('"hElLo WorlD"', '$.upper().lower().upper().replace("HELLO", "BYE")');
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye") starts with "bye"');
+select jsonb_path_query('"   hElLo WorlD "', '$.btrim().lower().upper().lower().replace("hello","bye") starts with "bye"');
+
 -- Test .time()
 select jsonb_path_query('null', '$.time()');
 select jsonb_path_query('true', '$.time()');
diff --git a/src/test/regress/sql/jsonpath.sql b/src/test/regress/sql/jsonpath.sql
index 61a5270d4e8..7dd2e57e7a6 100644
--- a/src/test/regress/sql/jsonpath.sql
+++ b/src/test/regress/sql/jsonpath.sql
@@ -78,6 +78,37 @@ select '$.boolean()'::jsonpath;
 select '$.date()'::jsonpath;
 select '$.decimal(4,2)'::jsonpath;
 select '$.string()'::jsonpath;
+select '$.replace("hello","bye")'::jsonpath;
+select '$.lower()'::jsonpath;
+select '$.upper()'::jsonpath;
+select '$.lower().upper().lower().replace("hello","bye")'::jsonpath;
+select '$.ltrim()'::jsonpath;
+select '$.ltrim("xyz")'::jsonpath;
+select '$.rtrim()'::jsonpath;
+select '$.rtrim("xyz")'::jsonpath;
+select '$.btrim()'::jsonpath;
+select '$.btrim("xyz")'::jsonpath;
+select '$.initcap()'::jsonpath;
+select '$.split_part("~@~", 2)'::jsonpath;
+
+-- Parse errors
+select '$.replace("hello")'::jsonpath;
+select '$.replace()'::jsonpath;
+select '$.replace("hello","bye","extra")'::jsonpath;
+select '$.split_part("~@~")'::jsonpath;
+select '$.split_part()'::jsonpath;
+select '$.split_part("~@~", "hi")'::jsonpath;
+select '$.split_part("~@~", 2, "extra")'::jsonpath;
+select '$.lower("hi")'::jsonpath;
+select '$.upper("hi")'::jsonpath;
+select '$.initcap("hi")'::jsonpath;
+select '$.ltrim(42)'::jsonpath;
+select '$.ltrim("x", "y")'::jsonpath;
+select '$.rtrim(42)'::jsonpath;
+select '$.rtrim("x", "y")'::jsonpath;
+select '$.trim(42)'::jsonpath;
+select '$.trim("x", "y")'::jsonpath;
+
 select '$.time()'::jsonpath;
 select '$.time(6)'::jsonpath;
 select '$.time_tz()'::jsonpath;
-- 
2.49.0

From 86704d1c079b205ccdcb79da974a690d4dca2ad3 Mon Sep 17 00:00:00 2001
From: "David E. Wheeler" <david@justatheory.com>
Date: Mon, 2 Jun 2025 17:14:10 -0400
Subject: [PATCH v7 1/2] Rename jsonpath method arg tokens

Rename the `csv_` tokens to `int_`, because they represent signed or
unsigned integers, as follows:

*   `csv_elem` => `int_elem`
*   `csv_list` => `int_list`
*   `opt_csv_list` => `opt_int_list`

Rename the `datetime_precision` tokens to `uint_arg`, as they represent
unsigned integers and will be useful for other methods in the future, as
follows:

*   `datetime_precision` => `uint_elem`
*   `opt_datetime_precision` => `opt_uint_arg`

Rename the `datetime_template` tokens to `str_arg`, as they represent
strings and will be useful for other methods in the future, as follows:

*   `datetime_template` => `str_elem`
*   `opt_datetime_template` => `opt_str_arg`
---
 src/backend/utils/adt/jsonpath_gram.y | 42 +++++++++++++--------------
 1 file changed, 21 insertions(+), 21 deletions(-)

diff --git a/src/backend/utils/adt/jsonpath_gram.y b/src/backend/utils/adt/jsonpath_gram.y
index 499745a8fef..0b16cec18c4 100644
--- a/src/backend/utils/adt/jsonpath_gram.y
+++ b/src/backend/utils/adt/jsonpath_gram.y
@@ -92,10 +92,10 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 %type	<value>		scalar_value path_primary expr array_accessor
 					any_path accessor_op key predicate delimited_predicate
 					index_elem starts_with_initial expr_or_predicate
-					datetime_template opt_datetime_template csv_elem
-					datetime_precision opt_datetime_precision
+					str_elem opt_str_arg int_elem
+					uint_elem opt_uint_arg
 
-%type	<elems>		accessor_expr csv_list opt_csv_list
+%type	<elems>		accessor_expr int_list opt_int_list
 
 %type	<indexs>	index_list
 
@@ -254,7 +254,7 @@ accessor_op:
 	| '.' any_path					{ $$ = $2; }
 	| '.' method '(' ')'			{ $$ = makeItemType($2); }
 	| '?' '(' predicate ')'			{ $$ = makeItemUnary(jpiFilter, $3); }
-	| '.' DECIMAL_P '(' opt_csv_list ')'
+	| '.' DECIMAL_P '(' opt_int_list ')'
 		{
 			if (list_length($4) == 0)
 				$$ = makeItemBinary(jpiDecimal, NULL, NULL);
@@ -268,19 +268,19 @@ accessor_op:
 						 errmsg("invalid input syntax for type %s", "jsonpath"),
 						 errdetail(".decimal() can only have an optional precision[,scale].")));
 		}
-	| '.' DATETIME_P '(' opt_datetime_template ')'
+	| '.' DATETIME_P '(' opt_str_arg ')'
 		{ $$ = makeItemUnary(jpiDatetime, $4); }
-	| '.' TIME_P '(' opt_datetime_precision ')'
+	| '.' TIME_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTime, $4); }
-	| '.' TIME_TZ_P '(' opt_datetime_precision ')'
+	| '.' TIME_TZ_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimeTz, $4); }
-	| '.' TIMESTAMP_P '(' opt_datetime_precision ')'
+	| '.' TIMESTAMP_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimestamp, $4); }
-	| '.' TIMESTAMP_TZ_P '(' opt_datetime_precision ')'
+	| '.' TIMESTAMP_TZ_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimestampTz, $4); }
 	;
 
-csv_elem:
+int_elem:
 	INT_P
 		{ $$ = makeItemNumeric(&$1); }
 	| '+' INT_P %prec UMINUS
@@ -289,31 +289,31 @@ csv_elem:
 		{ $$ = makeItemUnary(jpiMinus, makeItemNumeric(&$2)); }
 	;
 
-csv_list:
-	csv_elem						{ $$ = list_make1($1); }
-	| csv_list ',' csv_elem			{ $$ = lappend($1, $3); }
+int_list:
+	int_elem						{ $$ = list_make1($1); }
+	| int_list ',' int_elem			{ $$ = lappend($1, $3); }
 	;
 
-opt_csv_list:
-	csv_list						{ $$ = $1; }
+opt_int_list:
+	int_list						{ $$ = $1; }
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
-datetime_precision:
+uint_elem:
 	INT_P							{ $$ = makeItemNumeric(&$1); }
 	;
 
-opt_datetime_precision:
-	datetime_precision				{ $$ = $1; }
+opt_uint_arg:
+	uint_elem						{ $$ = $1; }
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
-datetime_template:
+str_elem:
 	STRING_P						{ $$ = makeItemString(&$1); }
 	;
 
-opt_datetime_template:
-	datetime_template				{ $$ = $1; }
+opt_str_arg:
+	str_elem						{ $$ = $1; }
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
-- 
2.49.0

From 1e80d72d20c466fc198043e059556d649adbaf5b Mon Sep 17 00:00:00 2001
From: Florents Tselai <florents.tselai@gmail.com>
Date: Tue, 3 Jun 2025 15:09:38 -0400
Subject: [PATCH v7 2/2] Add additional jsonpath string methods

Add the following jsonpath methods:

*   l/r/btrim()
*   lower(), upper()
*   initcap()
*   replace()
*   split_part()

Each simply dispatches to the standard string processing functions.
These depend on the locale, but since it's set at `initdb`, they can be
considered immutable and therefore allowed in any jsonpath expression.
---
 doc/src/sgml/func.sgml                       | 140 +++++++
 src/backend/utils/adt/jsonpath.c             | 113 +++++-
 src/backend/utils/adt/jsonpath_exec.c        | 200 ++++++++++
 src/backend/utils/adt/jsonpath_gram.y        |  28 +-
 src/backend/utils/adt/jsonpath_scan.l        |   8 +
 src/include/utils/jsonpath.h                 |   8 +
 src/test/regress/expected/jsonb_jsonpath.out | 399 +++++++++++++++++++
 src/test/regress/expected/jsonpath.out       | 137 +++++++
 src/test/regress/sql/jsonb_jsonpath.sql      | 109 +++++
 src/test/regress/sql/jsonpath.sql            |  31 ++
 10 files changed, 1169 insertions(+), 4 deletions(-)

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index c67688cbf5f..674c22c78d8 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -18627,6 +18627,146 @@ ERROR:  jsonpath member accessor can only be applied to an object
         <returnvalue>[{"id": 0, "key": "x", "value": "20"}, {"id": 0, "key": "y", "value": 32}]</returnvalue>
        </para></entry>
       </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>lower()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String converted to all lower case according to the rules of the database's locale.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"TOM"', '$.lower()')</literal>
+        <returnvalue>"tom"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>upper()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String converted to all upper case according to the rules of the database's locale.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"tom"', '$.upper()')</literal>
+        <returnvalue>"TOM"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>initcap()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the first letter of each word converted to upper case
+        according to the rules of the database's locale. Words are sequences
+        of alphanumeric characters separated by non-alphanumeric characters.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"hi THOMAS"', '$.initcap()')</literal>
+        <returnvalue>"Hi Thomas"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>replace(<replaceable>from</replaceable>, <replaceable>to</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with all occurrences of substring from replaced with substring to.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"abcdefabcdef"', '$.replace("cd", "XX")')</literal>
+        <returnvalue>"abXXefabXXef"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>split_part(<replaceable>delimiter</replaceable>, <replaceable>n</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String split at occurrences of <replaceable>delimiter</replaceable>
+        and returns the <replaceable>n</replaceable>'th field (counting from
+        one) or, when <replaceable>n</replaceable> is negative, returns the
+        |<replaceable>n</replaceable>|'th-from-last field.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)')</literal>
+        <returnvalue>"def"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"abc,def,ghi,jkl"', '$.split_part(",", 2)')</literal>
+        <returnvalue>"ghi"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>ltrim(<replaceable>characters</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the longest string containing only spaces or the
+        characters in <replaceable>characters</replaceable> removed from the
+        start of <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal> jsonb_path_query('"  hello"', '$.ltrim()')</literal>
+        <returnvalue>"hello"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"zzzytest"', '$.ltrim("xyz")')</literal>
+        <returnvalue>"test"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>rtrim([ <replaceable>characters</replaceable> ])</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the longest string containing only spaces or the
+        characters in <replaceable>characters</replaceable> removed from the
+        end of <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"hello  "', '$.rtrim()')</literal>
+        <returnvalue>"hello"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"testxxzx"', '$.rtrim("xyz")')</literal>
+        <returnvalue>"test"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>btrim([ <replaceable>characters</replaceable> ])</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the longest string containing only spaces or the
+        characters in <replaceable>characters</replaceable> removed from the
+        start and end of <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"  hello  "', '$.btrim()')</literal>
+        <returnvalue>"hello"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"xyxtrimyyx"', '$.btrim("xyz")')</literal>
+        <returnvalue>"trim"</returnvalue>
+       </para></entry>
+      </row>
+
      </tbody>
     </tgroup>
    </table>
diff --git a/src/backend/utils/adt/jsonpath.c b/src/backend/utils/adt/jsonpath.c
index 762f7e8a09d..0872b115697 100644
--- a/src/backend/utils/adt/jsonpath.c
+++ b/src/backend/utils/adt/jsonpath.c
@@ -298,6 +298,8 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 		case jpiMod:
 		case jpiStartsWith:
 		case jpiDecimal:
+		case jpiStrReplace:
+		case jpiStrSplitPart:
 			{
 				/*
 				 * First, reserve place for left/right arg's positions, then
@@ -362,6 +364,9 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 		case jpiTimeTz:
 		case jpiTimestamp:
 		case jpiTimestampTz:
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
 			{
 				int32		arg = reserveSpaceForItemPointer(buf);
 
@@ -457,6 +462,9 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 		case jpiInteger:
 		case jpiNumber:
 		case jpiStringFunc:
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrInitcap:
 			break;
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", item->type);
@@ -831,6 +839,60 @@ printJsonPathItem(StringInfo buf, JsonPathItem *v, bool inKey,
 			}
 			appendStringInfoChar(buf, ')');
 			break;
+		case jpiStrReplace:
+			appendStringInfoString(buf, ".replace(");
+			jspGetLeftArg(v, &elem);
+			printJsonPathItem(buf, &elem, false, false);
+			appendStringInfoChar(buf, ',');
+			jspGetRightArg(v, &elem);
+			printJsonPathItem(buf, &elem, false, false);
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrSplitPart:
+			appendStringInfoString(buf, ".split_part(");
+			jspGetLeftArg(v, &elem);
+			printJsonPathItem(buf, &elem, false, false);
+			appendStringInfoChar(buf, ',');
+			jspGetRightArg(v, &elem);
+			printJsonPathItem(buf, &elem, false, false);
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrLower:
+			appendStringInfoString(buf, ".lower()");
+			break;
+		case jpiStrUpper:
+			appendStringInfoString(buf, ".upper()");
+			break;
+		case jpiStrInitcap:
+			appendStringInfoString(buf, ".initcap()");
+			break;
+		case jpiStrLtrim:
+			appendStringInfoString(buf, ".ltrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrRtrim:
+			appendStringInfoString(buf, ".rtrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrBtrim:
+			appendStringInfoString(buf, ".btrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", v->type);
 	}
@@ -906,6 +968,12 @@ jspOperationName(JsonPathItemType type)
 			return "number";
 		case jpiStringFunc:
 			return "string";
+		case jpiStrReplace:
+			return "replace";
+		case jpiStrLower:
+			return "lower";
+		case jpiStrUpper:
+			return "upper";
 		case jpiTime:
 			return "time";
 		case jpiTimeTz:
@@ -914,6 +982,16 @@ jspOperationName(JsonPathItemType type)
 			return "timestamp";
 		case jpiTimestampTz:
 			return "timestamp_tz";
+		case jpiStrLtrim:
+			return "ltrim";
+		case jpiStrRtrim:
+			return "rtrim";
+		case jpiStrBtrim:
+			return "btrim";
+		case jpiStrInitcap:
+			return "initcap";
+		case jpiStrSplitPart:
+			return "split_part";
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", type);
 			return NULL;
@@ -1016,6 +1094,9 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 		case jpiInteger:
 		case jpiNumber:
 		case jpiStringFunc:
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrInitcap:
 			break;
 		case jpiString:
 		case jpiKey:
@@ -1041,6 +1122,8 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 		case jpiMod:
 		case jpiStartsWith:
 		case jpiDecimal:
+		case jpiStrReplace:
+		case jpiStrSplitPart:
 			read_int32(v->content.args.left, base, pos);
 			read_int32(v->content.args.right, base, pos);
 			break;
@@ -1055,6 +1138,9 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 		case jpiTimeTz:
 		case jpiTimestamp:
 		case jpiTimestampTz:
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
 			read_int32(v->content.arg, base, pos);
 			break;
 		case jpiIndexArray:
@@ -1090,7 +1176,10 @@ jspGetArg(JsonPathItem *v, JsonPathItem *a)
 		   v->type == jpiTime ||
 		   v->type == jpiTimeTz ||
 		   v->type == jpiTimestamp ||
-		   v->type == jpiTimestampTz);
+		   v->type == jpiTimestampTz ||
+		   v->type == jpiStrLtrim ||
+		   v->type == jpiStrRtrim ||
+		   v->type == jpiStrBtrim);
 
 	jspInitByBuffer(a, v->base, v->content.arg);
 }
@@ -1149,10 +1238,18 @@ jspGetNext(JsonPathItem *v, JsonPathItem *a)
 			   v->type == jpiInteger ||
 			   v->type == jpiNumber ||
 			   v->type == jpiStringFunc ||
+			   v->type == jpiStrReplace ||
+			   v->type == jpiStrLower ||
+			   v->type == jpiStrUpper ||
 			   v->type == jpiTime ||
 			   v->type == jpiTimeTz ||
 			   v->type == jpiTimestamp ||
-			   v->type == jpiTimestampTz);
+			   v->type == jpiTimestampTz ||
+			   v->type == jpiStrLtrim ||
+			   v->type == jpiStrRtrim ||
+			   v->type == jpiStrBtrim ||
+			   v->type == jpiStrInitcap ||
+			   v->type == jpiStrSplitPart);
 
 		if (a)
 			jspInitByBuffer(a, v->base, v->nextPos);
@@ -1201,7 +1298,9 @@ jspGetRightArg(JsonPathItem *v, JsonPathItem *a)
 		   v->type == jpiDiv ||
 		   v->type == jpiMod ||
 		   v->type == jpiStartsWith ||
-		   v->type == jpiDecimal);
+		   v->type == jpiDecimal ||
+		   v->type == jpiStrReplace ||
+		   v->type == jpiStrSplitPart);
 
 	jspInitByBuffer(a, v->base, v->content.args.right);
 }
@@ -1501,6 +1600,14 @@ jspIsMutableWalker(JsonPathItem *jpi, struct JsonPathMutableContext *cxt)
 			case jpiInteger:
 			case jpiNumber:
 			case jpiStringFunc:
+			case jpiStrReplace:
+			case jpiStrLower:
+			case jpiStrUpper:
+			case jpiStrLtrim:
+			case jpiStrRtrim:
+			case jpiStrBtrim:
+			case jpiStrInitcap:
+			case jpiStrSplitPart:
 				status = jpdsNonDateTime;
 				break;
 
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index dbab24737ef..2095f2a9c21 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -301,6 +301,8 @@ static JsonPathExecResult executeNumericItemMethod(JsonPathExecContext *cxt,
 												   JsonValueList *found);
 static JsonPathExecResult executeDateTimeMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
 												JsonbValue *jb, JsonValueList *found);
+static JsonPathExecResult executeStringInternalMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
+												JsonbValue *jb, JsonValueList *found);
 static JsonPathExecResult executeKeyValueMethod(JsonPathExecContext *cxt,
 												JsonPathItem *jsp, JsonbValue *jb, JsonValueList *found);
 static JsonPathExecResult appendBoolResult(JsonPathExecContext *cxt,
@@ -1659,6 +1661,23 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
 			}
 			break;
 
+		case jpiStrLtrim:
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrReplace:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
+		case jpiStrInitcap:
+		case jpiStrSplitPart:
+		{
+			if (unwrap && JsonbType(jb) == jbvArray)
+				return executeItemUnwrapTargetArray(cxt, jsp, jb, found, false);
+
+			return executeStringInternalMethod(cxt, jsp, jb, found);
+		}
+		break;
+
+
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", jsp->type);
 	}
@@ -2792,6 +2811,187 @@ executeDateTimeMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
 	return executeNextItem(cxt, jsp, &elem, jb, found, hasNext);
 }
 
+/*
+ * Implementation of .upper(), lower() et. al. methods,
+ * that forward their actual implementation to internal functions.
+ */
+static JsonPathExecResult executeStringInternalMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
+												JsonbValue *jb, JsonValueList *found) {
+	Assert(	jsp->type == jpiStrLower ||
+			jsp->type == jpiStrUpper ||
+			jsp->type == jpiStrReplace ||
+			jsp->type == jpiStrLtrim ||
+			jsp->type == jpiStrRtrim ||
+			jsp->type == jpiStrBtrim ||
+			jsp->type == jpiStrInitcap ||
+			jsp->type == jpiStrSplitPart);
+	JsonbValue	jbvbuf;
+	bool		hasNext;
+	JsonPathExecResult res = jperNotFound;
+	JsonPathItem elem;
+	Datum		str; /* Datum representation for the current string value. The first argument to internal functions */
+	char		*tmp = NULL;
+	char		*resStr = NULL;
+
+	if (!(jb = getScalar(jb, jbvString)))
+		RETURN_ERROR(ereport(ERROR,
+							 (errcode(ERRCODE_INVALID_ARGUMENT_FOR_SQL_JSON_DATETIME_FUNCTION),
+							  errmsg("jsonpath item method .%s() can only be applied to a string",
+									 jspOperationName(jsp->type)))));
+
+	tmp = pnstrdup(jb->val.string.val, jb->val.string.len);
+	str = CStringGetTextDatum(tmp);
+
+	/* Internal string functions that accept no arguments */
+	switch (jsp->type)
+	{
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
+		{
+			char	   *characters_str;
+			int			characters_len;
+			PGFunction	func = NULL;
+
+			if (jsp->content.arg)
+			{
+				switch (jsp->type)
+				{
+					case jpiStrLtrim:
+						func = ltrim;
+						break;
+					case jpiStrRtrim:
+						func = rtrim;
+						break;
+					case jpiStrBtrim:
+						func = btrim;
+						break;
+					default: ;
+				}
+				jspGetArg(jsp, &elem);
+				if (elem.type != jpiString)
+					elog(ERROR, "invalid jsonpath item type for .%s() argument", jspOperationName(jsp->type));
+
+				characters_str = jspGetString(&elem, &characters_len);
+				resStr = TextDatumGetCString(DirectFunctionCall2Coll(func,
+					DEFAULT_COLLATION_OID, str,
+					CStringGetTextDatum(characters_str)));
+				break;
+			}
+
+			switch (jsp->type)
+			{
+				case jpiStrLtrim:
+					func = ltrim1;
+					break;
+				case jpiStrRtrim:
+					func = rtrim1;
+					break;
+				case jpiStrBtrim:
+					func = btrim1;
+					break;
+				default: ;
+			}
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(func,
+					DEFAULT_COLLATION_OID, str));
+			break;
+		}
+
+		case jpiStrLower:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(lower, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiStrUpper:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(upper, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiStrInitcap:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(initcap, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiStrReplace:
+		{
+			char		*from_str, *to_str;
+			int			from_len, to_len;
+
+			jspGetLeftArg(jsp, &elem);
+			if (elem.type != jpiString)
+				elog(ERROR, "invalid jsonpath item type for .replace() from");
+
+			from_str = jspGetString(&elem, &from_len);
+
+			jspGetRightArg(jsp, &elem);
+			if (elem.type != jpiString)
+				elog(ERROR, "invalid jsonpath item type for .replace() to");
+
+			to_str = jspGetString(&elem, &to_len);
+
+			resStr = TextDatumGetCString(DirectFunctionCall3Coll(replace_text,
+				C_COLLATION_OID,
+				CStringGetTextDatum(tmp),
+				CStringGetTextDatum(from_str),
+				CStringGetTextDatum(to_str)));
+			break;
+		}
+		case jpiStrSplitPart:
+		{
+			char		*from_str;
+			Numeric		n;
+			int			from_len;
+
+			jspGetLeftArg(jsp, &elem);
+			if (elem.type != jpiString)
+				elog(ERROR, "invalid jsonpath item type for .split_part()");
+
+			from_str = jspGetString(&elem, &from_len);
+
+			jspGetRightArg(jsp, &elem);
+			if (elem.type != jpiNumeric)
+				elog(ERROR, "invalid jsonpath item type for .split_part()");
+
+			n = jspGetNumeric(&elem);
+
+			resStr = TextDatumGetCString(DirectFunctionCall3Coll(split_part,
+				C_COLLATION_OID,
+				CStringGetTextDatum(tmp),
+				CStringGetTextDatum(from_str),
+				DirectFunctionCall1(numeric_int8, NumericGetDatum(n))));
+			break;
+		}
+		default:
+			elog(ERROR, "unsupported jsonpath item type: %d", jsp->type);
+	}
+
+	if (resStr)
+		res = jperOk;
+
+	hasNext = jspGetNext(jsp, &elem);
+
+	if (!hasNext && !found)
+		return res;
+
+	jb = hasNext ? &jbvbuf : palloc(sizeof(*jb));
+
+	/* Create the appropriate jb value to return */
+	switch (jsp->type)
+	{
+		/* Cases for functions that return text */
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrReplace:
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
+		case jpiStrInitcap:
+		case jpiStrSplitPart:
+			jb->type = jbvString;
+			jb->val.string.val = resStr;
+			jb->val.string.len = strlen(jb->val.string.val);
+		default:
+			;
+			/* cant' happen */
+	}
+
+	return executeNextItem(cxt, jsp, &elem, jb, found, hasNext);
+}
+
 /*
  * Implementation of .keyvalue() method.
  *
diff --git a/src/backend/utils/adt/jsonpath_gram.y b/src/backend/utils/adt/jsonpath_gram.y
index 0b16cec18c4..d4bc3d6034b 100644
--- a/src/backend/utils/adt/jsonpath_gram.y
+++ b/src/backend/utils/adt/jsonpath_gram.y
@@ -86,6 +86,8 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 %token	<str>		DATETIME_P
 %token	<str>		BIGINT_P BOOLEAN_P DATE_P DECIMAL_P INTEGER_P NUMBER_P
 %token	<str>		STRINGFUNC_P TIME_P TIME_TZ_P TIMESTAMP_P TIMESTAMP_TZ_P
+%token	<str>		STR_REPLACE_P STR_LOWER_P STR_UPPER_P STR_LTRIM_P STR_RTRIM_P STR_BTRIM_P
+					STR_INITCAP_P STR_SPLIT_PART_P
 
 %type	<result>	result
 
@@ -95,7 +97,7 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 					str_elem opt_str_arg int_elem
 					uint_elem opt_uint_arg
 
-%type	<elems>		accessor_expr int_list opt_int_list
+%type	<elems>		accessor_expr int_list opt_int_list str_int_args str_str_args
 
 %type	<indexs>	index_list
 
@@ -278,6 +280,16 @@ accessor_op:
 		{ $$ = makeItemUnary(jpiTimestamp, $4); }
 	| '.' TIMESTAMP_TZ_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimestampTz, $4); }
+	| '.' STR_REPLACE_P '(' str_str_args ')'
+		{ $$ = makeItemBinary(jpiStrReplace, linitial($4), lsecond($4)); }
+	| '.' STR_SPLIT_PART_P '(' str_int_args ')'
+		{ $$ = makeItemBinary(jpiStrSplitPart, linitial($4), lsecond($4)); }
+	| '.' STR_LTRIM_P '(' opt_str_arg ')'
+		{ $$ = makeItemUnary(jpiStrLtrim, $4); }
+	| '.' STR_RTRIM_P '(' opt_str_arg ')'
+		{ $$ = makeItemUnary(jpiStrRtrim, $4); }
+	| '.' STR_BTRIM_P '(' opt_str_arg ')'
+		{ $$ = makeItemUnary(jpiStrBtrim, $4); }
 	;
 
 int_elem:
@@ -317,6 +329,14 @@ opt_str_arg:
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
+str_int_args:
+	str_elem ',' int_elem			{ $$ = list_make2($1, $3) }
+	;
+
+str_str_args:
+	str_elem ',' str_elem 			{ $$ = list_make2($1, $3) }
+	;
+
 key:
 	key_name						{ $$ = makeItemKey(&$1); }
 	;
@@ -357,6 +377,9 @@ key_name:
 	| TIME_TZ_P
 	| TIMESTAMP_P
 	| TIMESTAMP_TZ_P
+	| STR_LTRIM_P
+	| STR_RTRIM_P
+	| STR_BTRIM_P
 	;
 
 method:
@@ -373,6 +396,9 @@ method:
 	| INTEGER_P						{ $$ = jpiInteger; }
 	| NUMBER_P						{ $$ = jpiNumber; }
 	| STRINGFUNC_P					{ $$ = jpiStringFunc; }
+	| STR_LOWER_P					{ $$ = jpiStrLower; }
+	| STR_UPPER_P					{ $$ = jpiStrUpper; }
+	| STR_INITCAP_P					{ $$ = jpiStrInitcap; }
 	;
 %%
 
diff --git a/src/backend/utils/adt/jsonpath_scan.l b/src/backend/utils/adt/jsonpath_scan.l
index c7aab83eeb4..69c61f98500 100644
--- a/src/backend/utils/adt/jsonpath_scan.l
+++ b/src/backend/utils/adt/jsonpath_scan.l
@@ -413,8 +413,13 @@ static const JsonPathKeyword keywords[] = {
 	{4, true, TRUE_P, "true"},
 	{4, false, TYPE_P, "type"},
 	{4, false, WITH_P, "with"},
+	{5, false, STR_BTRIM_P, "btrim"},
 	{5, true, FALSE_P, "false"},
 	{5, false, FLOOR_P, "floor"},
+	{5, false, STR_LOWER_P, "lower"},
+	{5, false, STR_LTRIM_P, "ltrim"},
+	{5, false, STR_RTRIM_P, "rtrim"},
+	{5, false, STR_UPPER_P, "upper"},
 	{6, false, BIGINT_P, "bigint"},
 	{6, false, DOUBLE_P, "double"},
 	{6, false, EXISTS_P, "exists"},
@@ -425,13 +430,16 @@ static const JsonPathKeyword keywords[] = {
 	{7, false, BOOLEAN_P, "boolean"},
 	{7, false, CEILING_P, "ceiling"},
 	{7, false, DECIMAL_P, "decimal"},
+	{7, false, STR_INITCAP_P, "initcap"},
 	{7, false, INTEGER_P, "integer"},
+	{7, false, STR_REPLACE_P, "replace"},
 	{7, false, TIME_TZ_P, "time_tz"},
 	{7, false, UNKNOWN_P, "unknown"},
 	{8, false, DATETIME_P, "datetime"},
 	{8, false, KEYVALUE_P, "keyvalue"},
 	{9, false, TIMESTAMP_P, "timestamp"},
 	{10, false, LIKE_REGEX_P, "like_regex"},
+	{10,false, STR_SPLIT_PART_P, "split_part"},
 	{12, false, TIMESTAMP_TZ_P, "timestamp_tz"},
 };
 
diff --git a/src/include/utils/jsonpath.h b/src/include/utils/jsonpath.h
index 23a76d233e9..2d0c53f7b06 100644
--- a/src/include/utils/jsonpath.h
+++ b/src/include/utils/jsonpath.h
@@ -115,6 +115,14 @@ typedef enum JsonPathItemType
 	jpiTimeTz,					/* .time_tz() item method */
 	jpiTimestamp,				/* .timestamp() item method */
 	jpiTimestampTz,				/* .timestamp_tz() item method */
+	jpiStrReplace,				/* .replace() item method */
+	jpiStrLower,				/* .lower() item method */
+	jpiStrUpper,				/* .upper() item method */
+	jpiStrLtrim,				/* .ltrim() item method */
+	jpiStrRtrim,				/* .rtrim() item method */
+	jpiStrBtrim,				/* .btrim() item method */
+	jpiStrInitcap,				/* .initcap() item method */
+	jpiStrSplitPart,			/* .split_part() item method */
 } JsonPathItemType;
 
 /* XQuery regex mode flags for LIKE_REGEX predicate */
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e91a29..cea539717f9 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -2723,6 +2723,405 @@ select jsonb_path_query('"2023-08-15 12:34:56"', '$.timestamp().string()');
 (1 row)
 
 rollback;
+-- test .ltrim()
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"zzzytest"', '$.ltrim("xyz")');
+ jsonb_path_query 
+------------------
+ "test"
+(1 row)
+
+select jsonb_path_query('null', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('null', '$.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.ltrim()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('{}', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('true', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('1234', '$.ltrim().type()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim()');
+  jsonb_path_query_array  
+--------------------------
+ ["maybe  ", "yes", "no"]
+(1 row)
+
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .rtrim()
+select jsonb_path_query('"   hello   "', '$.rtrim(" ")');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+select jsonb_path_query('"testxxzx"', '$.rtrim("xyz")');
+ jsonb_path_query 
+------------------
+ "test"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+-- test .btrim()
+select jsonb_path_query('"   hello   "', '$.btrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+select jsonb_path_query('"xyxtrimyyx"', '$.btrim("xyz")');
+ jsonb_path_query 
+------------------
+ "trim"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.btrim()');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.btrim()');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+-- test .lower()
+select jsonb_path_query('null', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('null', '$.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.lower()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('{}', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.lower()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.lower()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('true', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('1234', '$.lower().type()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower()');
+ jsonb_path_query_array 
+------------------------
+ ["maybe", "yes", "no"]
+(1 row)
+
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .upper()
+select jsonb_path_query('null', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('null', '$.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.upper()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('{}', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.upper()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.upper()');
+ jsonb_path_query 
+------------------
+ "1.23AAA"
+(1 row)
+
+select jsonb_path_query('1234', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('true', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('1234', '$.upper().type()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper()');
+ jsonb_path_query_array 
+------------------------
+ ["MAYBE", "YES", "NO"]
+(1 row)
+
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .initcap()
+select jsonb_path_query('null', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('null', '$.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.initcap()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('{}', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('true', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('1234', '$.initcap().type()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('["maybe yes", "probably no"]', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "Maybe Yes"
+ "Probably No"
+(2 rows)
+
+-- Test .replace()
+select jsonb_path_query('null', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('null', '$.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('["x", "y", "z"]', '$.replace("x", "bye")');
+ jsonb_path_query 
+------------------
+ "bye"
+ "y"
+ "z"
+(3 rows)
+
+select jsonb_path_query('{}', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('"hello world"', '$.replace("hello","bye")');
+ jsonb_path_query 
+------------------
+ "bye world"
+(1 row)
+
+select jsonb_path_query('"hello world"', '$.replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
+-- Test .split_part()
+select jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)');
+ jsonb_path_query 
+------------------
+ "def"
+(1 row)
+
+select jsonb_path_query('"abc,def,ghi,jkl"', '$.split_part(",", -2)');
+ jsonb_path_query 
+------------------
+ "ghi"
+(1 row)
+
+-- Test string methods play nicely together
+select jsonb_path_query('"hello world"', '$.replace("hello","bye").upper()');
+ jsonb_path_query 
+------------------
+ "BYE WORLD"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye")');
+ jsonb_path_query 
+------------------
+ "bye world"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.upper().lower().upper().replace("HELLO", "BYE")');
+ jsonb_path_query 
+------------------
+ "BYE WORLD"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
+select jsonb_path_query('"   hElLo WorlD "', '$.btrim().lower().upper().lower().replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
 -- Test .time()
 select jsonb_path_query('null', '$.time()');
 ERROR:  jsonpath item method .time() can only be applied to a string
diff --git a/src/test/regress/expected/jsonpath.out b/src/test/regress/expected/jsonpath.out
index fd9bd755f52..a13022feabd 100644
--- a/src/test/regress/expected/jsonpath.out
+++ b/src/test/regress/expected/jsonpath.out
@@ -435,6 +435,143 @@ select '$.string()'::jsonpath;
  $.string()
 (1 row)
 
+select '$.replace("hello","bye")'::jsonpath;
+         jsonpath         
+--------------------------
+ $.replace("hello","bye")
+(1 row)
+
+select '$.lower()'::jsonpath;
+ jsonpath  
+-----------
+ $.lower()
+(1 row)
+
+select '$.upper()'::jsonpath;
+ jsonpath  
+-----------
+ $.upper()
+(1 row)
+
+select '$.lower().upper().lower().replace("hello","bye")'::jsonpath;
+                     jsonpath                     
+--------------------------------------------------
+ $.lower().upper().lower().replace("hello","bye")
+(1 row)
+
+select '$.ltrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.ltrim()
+(1 row)
+
+select '$.ltrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.ltrim("xyz")
+(1 row)
+
+select '$.rtrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.rtrim()
+(1 row)
+
+select '$.rtrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.rtrim("xyz")
+(1 row)
+
+select '$.btrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.btrim()
+(1 row)
+
+select '$.btrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.btrim("xyz")
+(1 row)
+
+select '$.initcap()'::jsonpath;
+  jsonpath   
+-------------
+ $.initcap()
+(1 row)
+
+select '$.split_part("~@~", 2)'::jsonpath;
+       jsonpath        
+-----------------------
+ $.split_part("~@~",2)
+(1 row)
+
+-- Parse errors
+select '$.replace("hello")'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.replace("hello")'::jsonpath;
+               ^
+select '$.replace()'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.replace()'::jsonpath;
+               ^
+select '$.replace("hello","bye","extra")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.replace("hello","bye","extra")'::jsonpath;
+               ^
+select '$.split_part("~@~")'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.split_part("~@~")'::jsonpath;
+               ^
+select '$.split_part()'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.split_part()'::jsonpath;
+               ^
+select '$.split_part("~@~", "hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.split_part("~@~", "hi")'::jsonpath;
+               ^
+select '$.split_part("~@~", 2, "extra")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.split_part("~@~", 2, "extra")'::jsonpath;
+               ^
+select '$.lower("hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.lower("hi")'::jsonpath;
+               ^
+select '$.upper("hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.upper("hi")'::jsonpath;
+               ^
+select '$.initcap("hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.initcap("hi")'::jsonpath;
+               ^
+select '$.ltrim(42)'::jsonpath;
+ERROR:  syntax error at or near "42" of jsonpath input
+LINE 1: select '$.ltrim(42)'::jsonpath;
+               ^
+select '$.ltrim("x", "y")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.ltrim("x", "y")'::jsonpath;
+               ^
+select '$.rtrim(42)'::jsonpath;
+ERROR:  syntax error at or near "42" of jsonpath input
+LINE 1: select '$.rtrim(42)'::jsonpath;
+               ^
+select '$.rtrim("x", "y")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.rtrim("x", "y")'::jsonpath;
+               ^
+select '$.trim(42)'::jsonpath;
+ERROR:  syntax error at or near "(" of jsonpath input
+LINE 1: select '$.trim(42)'::jsonpath;
+               ^
+select '$.trim("x", "y")'::jsonpath;
+ERROR:  syntax error at or near "(" of jsonpath input
+LINE 1: select '$.trim("x", "y")'::jsonpath;
+               ^
 select '$.time()'::jsonpath;
  jsonpath 
 ----------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a5269..8169719343e 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -623,6 +623,115 @@ select jsonb_path_query('"2023-08-15 12:34:56 +5:30"', '$.timestamp_tz().string(
 select jsonb_path_query('"2023-08-15 12:34:56"', '$.timestamp().string()');
 rollback;
 
+-- test .ltrim()
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+select jsonb_path_query('"   hello   "', '$.ltrim()');
+select jsonb_path_query('"zzzytest"', '$.ltrim("xyz")');
+select jsonb_path_query('null', '$.ltrim()');
+select jsonb_path_query('null', '$.ltrim()', silent => true);
+select jsonb_path_query('[]', '$.ltrim()');
+select jsonb_path_query('[]', 'strict $.ltrim()');
+select jsonb_path_query('{}', '$.ltrim()');
+select jsonb_path_query('[]', 'strict $.ltrim()', silent => true);
+select jsonb_path_query('{}', '$.ltrim()', silent => true);
+select jsonb_path_query('1.23', '$.ltrim()');
+select jsonb_path_query('"1.23"', '$.ltrim()');
+select jsonb_path_query('"1.23aaa"', '$.ltrim()');
+select jsonb_path_query('1234', '$.ltrim()');
+select jsonb_path_query('true', '$.ltrim()');
+select jsonb_path_query('1234', '$.ltrim().type()');
+select jsonb_path_query('[2, true]', '$.ltrim()');
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim()');
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim().type()');
+
+-- test .rtrim()
+select jsonb_path_query('"   hello   "', '$.rtrim(" ")');
+select jsonb_path_query('"testxxzx"', '$.rtrim("xyz")');
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+
+-- test .btrim()
+select jsonb_path_query('"   hello   "', '$.btrim(" ")');
+select jsonb_path_query('"xyxtrimyyx"', '$.btrim("xyz")');
+select jsonb_path_query('"   hello   "', '$.btrim()');
+select jsonb_path_query('"   hello   "', '$.btrim()');
+
+-- test .lower()
+select jsonb_path_query('null', '$.lower()');
+select jsonb_path_query('null', '$.lower()', silent => true);
+select jsonb_path_query('[]', '$.lower()');
+select jsonb_path_query('[]', 'strict $.lower()');
+select jsonb_path_query('{}', '$.lower()');
+select jsonb_path_query('[]', 'strict $.lower()', silent => true);
+select jsonb_path_query('{}', '$.lower()', silent => true);
+select jsonb_path_query('1.23', '$.lower()');
+select jsonb_path_query('"1.23"', '$.lower()');
+select jsonb_path_query('"1.23aaa"', '$.lower()');
+select jsonb_path_query('1234', '$.lower()');
+select jsonb_path_query('true', '$.lower()');
+select jsonb_path_query('1234', '$.lower().type()');
+select jsonb_path_query('[2, true]', '$.lower()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower().type()');
+
+-- test .upper()
+select jsonb_path_query('null', '$.upper()');
+select jsonb_path_query('null', '$.upper()', silent => true);
+select jsonb_path_query('[]', '$.upper()');
+select jsonb_path_query('[]', 'strict $.upper()');
+select jsonb_path_query('{}', '$.upper()');
+select jsonb_path_query('[]', 'strict $.upper()', silent => true);
+select jsonb_path_query('{}', '$.upper()', silent => true);
+select jsonb_path_query('1.23', '$.upper()');
+select jsonb_path_query('"1.23"', '$.upper()');
+select jsonb_path_query('"1.23aaa"', '$.upper()');
+select jsonb_path_query('1234', '$.upper()');
+select jsonb_path_query('true', '$.upper()');
+select jsonb_path_query('1234', '$.upper().type()');
+select jsonb_path_query('[2, true]', '$.upper()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper().type()');
+
+-- test .initcap()
+select jsonb_path_query('null', '$.initcap()');
+select jsonb_path_query('null', '$.initcap()', silent => true);
+select jsonb_path_query('[]', '$.initcap()');
+select jsonb_path_query('[]', 'strict $.initcap()');
+select jsonb_path_query('{}', '$.initcap()');
+select jsonb_path_query('[]', 'strict $.initcap()', silent => true);
+select jsonb_path_query('{}', '$.initcap()', silent => true);
+select jsonb_path_query('1.23', '$.initcap()');
+select jsonb_path_query('"1.23"', '$.initcap()');
+select jsonb_path_query('"1.23aaa"', '$.initcap()');
+select jsonb_path_query('1234', '$.initcap()');
+select jsonb_path_query('true', '$.initcap()');
+select jsonb_path_query('1234', '$.initcap().type()');
+select jsonb_path_query('[2, true]', '$.initcap()');
+select jsonb_path_query('["maybe yes", "probably no"]', '$.initcap()');
+
+-- Test .replace()
+select jsonb_path_query('null', '$.replace("x", "bye")');
+select jsonb_path_query('null', '$.replace("x", "bye")', silent => true);
+select jsonb_path_query('["x", "y", "z"]', '$.replace("x", "bye")');
+select jsonb_path_query('{}', '$.replace("x", "bye")');
+select jsonb_path_query('[]', 'strict $.replace("x", "bye")', silent => true);
+select jsonb_path_query('{}', '$.replace("x", "bye")', silent => true);
+select jsonb_path_query('1.23', '$.replace("x", "bye")');
+select jsonb_path_query('"hello world"', '$.replace("hello","bye")');
+select jsonb_path_query('"hello world"', '$.replace("hello","bye") starts with "bye"');
+
+-- Test .split_part()
+select jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)');
+select jsonb_path_query('"abc,def,ghi,jkl"', '$.split_part(",", -2)');
+
+-- Test string methods play nicely together
+select jsonb_path_query('"hello world"', '$.replace("hello","bye").upper()');
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye")');
+select jsonb_path_query('"hElLo WorlD"', '$.upper().lower().upper().replace("HELLO", "BYE")');
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye") starts with "bye"');
+select jsonb_path_query('"   hElLo WorlD "', '$.btrim().lower().upper().lower().replace("hello","bye") starts with "bye"');
+
 -- Test .time()
 select jsonb_path_query('null', '$.time()');
 select jsonb_path_query('true', '$.time()');
diff --git a/src/test/regress/sql/jsonpath.sql b/src/test/regress/sql/jsonpath.sql
index 61a5270d4e8..7dd2e57e7a6 100644
--- a/src/test/regress/sql/jsonpath.sql
+++ b/src/test/regress/sql/jsonpath.sql
@@ -78,6 +78,37 @@ select '$.boolean()'::jsonpath;
 select '$.date()'::jsonpath;
 select '$.decimal(4,2)'::jsonpath;
 select '$.string()'::jsonpath;
+select '$.replace("hello","bye")'::jsonpath;
+select '$.lower()'::jsonpath;
+select '$.upper()'::jsonpath;
+select '$.lower().upper().lower().replace("hello","bye")'::jsonpath;
+select '$.ltrim()'::jsonpath;
+select '$.ltrim("xyz")'::jsonpath;
+select '$.rtrim()'::jsonpath;
+select '$.rtrim("xyz")'::jsonpath;
+select '$.btrim()'::jsonpath;
+select '$.btrim("xyz")'::jsonpath;
+select '$.initcap()'::jsonpath;
+select '$.split_part("~@~", 2)'::jsonpath;
+
+-- Parse errors
+select '$.replace("hello")'::jsonpath;
+select '$.replace()'::jsonpath;
+select '$.replace("hello","bye","extra")'::jsonpath;
+select '$.split_part("~@~")'::jsonpath;
+select '$.split_part()'::jsonpath;
+select '$.split_part("~@~", "hi")'::jsonpath;
+select '$.split_part("~@~", 2, "extra")'::jsonpath;
+select '$.lower("hi")'::jsonpath;
+select '$.upper("hi")'::jsonpath;
+select '$.initcap("hi")'::jsonpath;
+select '$.ltrim(42)'::jsonpath;
+select '$.ltrim("x", "y")'::jsonpath;
+select '$.rtrim(42)'::jsonpath;
+select '$.rtrim("x", "y")'::jsonpath;
+select '$.trim(42)'::jsonpath;
+select '$.trim("x", "y")'::jsonpath;
+
 select '$.time()'::jsonpath;
 select '$.time(6)'::jsonpath;
 select '$.time_tz()'::jsonpath;
-- 
2.49.0

From 86704d1c079b205ccdcb79da974a690d4dca2ad3 Mon Sep 17 00:00:00 2001
From: "David E. Wheeler" <david@justatheory.com>
Date: Mon, 2 Jun 2025 17:14:10 -0400
Subject: [PATCH v8 1/2] Rename jsonpath method arg tokens

Rename the `csv_` tokens to `int_`, because they represent signed or
unsigned integers, as follows:

*   `csv_elem` => `int_elem`
*   `csv_list` => `int_list`
*   `opt_csv_list` => `opt_int_list`

Rename the `datetime_precision` tokens to `uint_arg`, as they represent
unsigned integers and will be useful for other methods in the future, as
follows:

*   `datetime_precision` => `uint_elem`
*   `opt_datetime_precision` => `opt_uint_arg`

Rename the `datetime_template` tokens to `str_arg`, as they represent
strings and will be useful for other methods in the future, as follows:

*   `datetime_template` => `str_elem`
*   `opt_datetime_template` => `opt_str_arg`
---
 src/backend/utils/adt/jsonpath_gram.y | 42 +++++++++++++--------------
 1 file changed, 21 insertions(+), 21 deletions(-)

diff --git a/src/backend/utils/adt/jsonpath_gram.y b/src/backend/utils/adt/jsonpath_gram.y
index 499745a8fef..0b16cec18c4 100644
--- a/src/backend/utils/adt/jsonpath_gram.y
+++ b/src/backend/utils/adt/jsonpath_gram.y
@@ -92,10 +92,10 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 %type	<value>		scalar_value path_primary expr array_accessor
 					any_path accessor_op key predicate delimited_predicate
 					index_elem starts_with_initial expr_or_predicate
-					datetime_template opt_datetime_template csv_elem
-					datetime_precision opt_datetime_precision
+					str_elem opt_str_arg int_elem
+					uint_elem opt_uint_arg
 
-%type	<elems>		accessor_expr csv_list opt_csv_list
+%type	<elems>		accessor_expr int_list opt_int_list
 
 %type	<indexs>	index_list
 
@@ -254,7 +254,7 @@ accessor_op:
 	| '.' any_path					{ $$ = $2; }
 	| '.' method '(' ')'			{ $$ = makeItemType($2); }
 	| '?' '(' predicate ')'			{ $$ = makeItemUnary(jpiFilter, $3); }
-	| '.' DECIMAL_P '(' opt_csv_list ')'
+	| '.' DECIMAL_P '(' opt_int_list ')'
 		{
 			if (list_length($4) == 0)
 				$$ = makeItemBinary(jpiDecimal, NULL, NULL);
@@ -268,19 +268,19 @@ accessor_op:
 						 errmsg("invalid input syntax for type %s", "jsonpath"),
 						 errdetail(".decimal() can only have an optional precision[,scale].")));
 		}
-	| '.' DATETIME_P '(' opt_datetime_template ')'
+	| '.' DATETIME_P '(' opt_str_arg ')'
 		{ $$ = makeItemUnary(jpiDatetime, $4); }
-	| '.' TIME_P '(' opt_datetime_precision ')'
+	| '.' TIME_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTime, $4); }
-	| '.' TIME_TZ_P '(' opt_datetime_precision ')'
+	| '.' TIME_TZ_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimeTz, $4); }
-	| '.' TIMESTAMP_P '(' opt_datetime_precision ')'
+	| '.' TIMESTAMP_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimestamp, $4); }
-	| '.' TIMESTAMP_TZ_P '(' opt_datetime_precision ')'
+	| '.' TIMESTAMP_TZ_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimestampTz, $4); }
 	;
 
-csv_elem:
+int_elem:
 	INT_P
 		{ $$ = makeItemNumeric(&$1); }
 	| '+' INT_P %prec UMINUS
@@ -289,31 +289,31 @@ csv_elem:
 		{ $$ = makeItemUnary(jpiMinus, makeItemNumeric(&$2)); }
 	;
 
-csv_list:
-	csv_elem						{ $$ = list_make1($1); }
-	| csv_list ',' csv_elem			{ $$ = lappend($1, $3); }
+int_list:
+	int_elem						{ $$ = list_make1($1); }
+	| int_list ',' int_elem			{ $$ = lappend($1, $3); }
 	;
 
-opt_csv_list:
-	csv_list						{ $$ = $1; }
+opt_int_list:
+	int_list						{ $$ = $1; }
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
-datetime_precision:
+uint_elem:
 	INT_P							{ $$ = makeItemNumeric(&$1); }
 	;
 
-opt_datetime_precision:
-	datetime_precision				{ $$ = $1; }
+opt_uint_arg:
+	uint_elem						{ $$ = $1; }
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
-datetime_template:
+str_elem:
 	STRING_P						{ $$ = makeItemString(&$1); }
 	;
 
-opt_datetime_template:
-	datetime_template				{ $$ = $1; }
+opt_str_arg:
+	str_elem						{ $$ = $1; }
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
-- 
2.49.0

From 8f2146ad7c27a9b2aa094878e647c6bb6327df9b Mon Sep 17 00:00:00 2001
From: Florents Tselai <florents.tselai@gmail.com>
Date: Wed, 4 Jun 2025 11:21:23 -0400
Subject: [PATCH v8 2/2] Add additional jsonpath string methods

Add the following jsonpath methods:

*   l/r/btrim()
*   lower(), upper()
*   initcap()
*   replace()
*   split_part()

Each simply dispatches to the standard string processing functions.
These depend on the locale, but since it's set at `initdb`, they can be
considered immutable and therefore allowed in any jsonpath expression.
---
 doc/src/sgml/func.sgml                       | 140 +++++++
 src/backend/utils/adt/jsonpath.c             | 113 +++++-
 src/backend/utils/adt/jsonpath_exec.c        | 206 ++++++++++
 src/backend/utils/adt/jsonpath_gram.y        |  28 +-
 src/backend/utils/adt/jsonpath_scan.l        |   8 +
 src/include/utils/jsonpath.h                 |   8 +
 src/test/regress/expected/jsonb_jsonpath.out | 399 +++++++++++++++++++
 src/test/regress/expected/jsonpath.out       | 137 +++++++
 src/test/regress/sql/jsonb_jsonpath.sql      | 109 +++++
 src/test/regress/sql/jsonpath.sql            |  31 ++
 10 files changed, 1175 insertions(+), 4 deletions(-)

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index c67688cbf5f..674c22c78d8 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -18627,6 +18627,146 @@ ERROR:  jsonpath member accessor can only be applied to an object
         <returnvalue>[{"id": 0, "key": "x", "value": "20"}, {"id": 0, "key": "y", "value": 32}]</returnvalue>
        </para></entry>
       </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>lower()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String converted to all lower case according to the rules of the database's locale.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"TOM"', '$.lower()')</literal>
+        <returnvalue>"tom"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>upper()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String converted to all upper case according to the rules of the database's locale.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"tom"', '$.upper()')</literal>
+        <returnvalue>"TOM"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>initcap()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the first letter of each word converted to upper case
+        according to the rules of the database's locale. Words are sequences
+        of alphanumeric characters separated by non-alphanumeric characters.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"hi THOMAS"', '$.initcap()')</literal>
+        <returnvalue>"Hi Thomas"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>replace(<replaceable>from</replaceable>, <replaceable>to</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with all occurrences of substring from replaced with substring to.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"abcdefabcdef"', '$.replace("cd", "XX")')</literal>
+        <returnvalue>"abXXefabXXef"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>split_part(<replaceable>delimiter</replaceable>, <replaceable>n</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String split at occurrences of <replaceable>delimiter</replaceable>
+        and returns the <replaceable>n</replaceable>'th field (counting from
+        one) or, when <replaceable>n</replaceable> is negative, returns the
+        |<replaceable>n</replaceable>|'th-from-last field.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)')</literal>
+        <returnvalue>"def"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"abc,def,ghi,jkl"', '$.split_part(",", 2)')</literal>
+        <returnvalue>"ghi"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>ltrim(<replaceable>characters</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the longest string containing only spaces or the
+        characters in <replaceable>characters</replaceable> removed from the
+        start of <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal> jsonb_path_query('"  hello"', '$.ltrim()')</literal>
+        <returnvalue>"hello"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"zzzytest"', '$.ltrim("xyz")')</literal>
+        <returnvalue>"test"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>rtrim([ <replaceable>characters</replaceable> ])</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the longest string containing only spaces or the
+        characters in <replaceable>characters</replaceable> removed from the
+        end of <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"hello  "', '$.rtrim()')</literal>
+        <returnvalue>"hello"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"testxxzx"', '$.rtrim("xyz")')</literal>
+        <returnvalue>"test"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>btrim([ <replaceable>characters</replaceable> ])</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the longest string containing only spaces or the
+        characters in <replaceable>characters</replaceable> removed from the
+        start and end of <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"  hello  "', '$.btrim()')</literal>
+        <returnvalue>"hello"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"xyxtrimyyx"', '$.btrim("xyz")')</literal>
+        <returnvalue>"trim"</returnvalue>
+       </para></entry>
+      </row>
+
      </tbody>
     </tgroup>
    </table>
diff --git a/src/backend/utils/adt/jsonpath.c b/src/backend/utils/adt/jsonpath.c
index 762f7e8a09d..0872b115697 100644
--- a/src/backend/utils/adt/jsonpath.c
+++ b/src/backend/utils/adt/jsonpath.c
@@ -298,6 +298,8 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 		case jpiMod:
 		case jpiStartsWith:
 		case jpiDecimal:
+		case jpiStrReplace:
+		case jpiStrSplitPart:
 			{
 				/*
 				 * First, reserve place for left/right arg's positions, then
@@ -362,6 +364,9 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 		case jpiTimeTz:
 		case jpiTimestamp:
 		case jpiTimestampTz:
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
 			{
 				int32		arg = reserveSpaceForItemPointer(buf);
 
@@ -457,6 +462,9 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 		case jpiInteger:
 		case jpiNumber:
 		case jpiStringFunc:
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrInitcap:
 			break;
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", item->type);
@@ -831,6 +839,60 @@ printJsonPathItem(StringInfo buf, JsonPathItem *v, bool inKey,
 			}
 			appendStringInfoChar(buf, ')');
 			break;
+		case jpiStrReplace:
+			appendStringInfoString(buf, ".replace(");
+			jspGetLeftArg(v, &elem);
+			printJsonPathItem(buf, &elem, false, false);
+			appendStringInfoChar(buf, ',');
+			jspGetRightArg(v, &elem);
+			printJsonPathItem(buf, &elem, false, false);
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrSplitPart:
+			appendStringInfoString(buf, ".split_part(");
+			jspGetLeftArg(v, &elem);
+			printJsonPathItem(buf, &elem, false, false);
+			appendStringInfoChar(buf, ',');
+			jspGetRightArg(v, &elem);
+			printJsonPathItem(buf, &elem, false, false);
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrLower:
+			appendStringInfoString(buf, ".lower()");
+			break;
+		case jpiStrUpper:
+			appendStringInfoString(buf, ".upper()");
+			break;
+		case jpiStrInitcap:
+			appendStringInfoString(buf, ".initcap()");
+			break;
+		case jpiStrLtrim:
+			appendStringInfoString(buf, ".ltrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrRtrim:
+			appendStringInfoString(buf, ".rtrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrBtrim:
+			appendStringInfoString(buf, ".btrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", v->type);
 	}
@@ -906,6 +968,12 @@ jspOperationName(JsonPathItemType type)
 			return "number";
 		case jpiStringFunc:
 			return "string";
+		case jpiStrReplace:
+			return "replace";
+		case jpiStrLower:
+			return "lower";
+		case jpiStrUpper:
+			return "upper";
 		case jpiTime:
 			return "time";
 		case jpiTimeTz:
@@ -914,6 +982,16 @@ jspOperationName(JsonPathItemType type)
 			return "timestamp";
 		case jpiTimestampTz:
 			return "timestamp_tz";
+		case jpiStrLtrim:
+			return "ltrim";
+		case jpiStrRtrim:
+			return "rtrim";
+		case jpiStrBtrim:
+			return "btrim";
+		case jpiStrInitcap:
+			return "initcap";
+		case jpiStrSplitPart:
+			return "split_part";
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", type);
 			return NULL;
@@ -1016,6 +1094,9 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 		case jpiInteger:
 		case jpiNumber:
 		case jpiStringFunc:
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrInitcap:
 			break;
 		case jpiString:
 		case jpiKey:
@@ -1041,6 +1122,8 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 		case jpiMod:
 		case jpiStartsWith:
 		case jpiDecimal:
+		case jpiStrReplace:
+		case jpiStrSplitPart:
 			read_int32(v->content.args.left, base, pos);
 			read_int32(v->content.args.right, base, pos);
 			break;
@@ -1055,6 +1138,9 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 		case jpiTimeTz:
 		case jpiTimestamp:
 		case jpiTimestampTz:
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
 			read_int32(v->content.arg, base, pos);
 			break;
 		case jpiIndexArray:
@@ -1090,7 +1176,10 @@ jspGetArg(JsonPathItem *v, JsonPathItem *a)
 		   v->type == jpiTime ||
 		   v->type == jpiTimeTz ||
 		   v->type == jpiTimestamp ||
-		   v->type == jpiTimestampTz);
+		   v->type == jpiTimestampTz ||
+		   v->type == jpiStrLtrim ||
+		   v->type == jpiStrRtrim ||
+		   v->type == jpiStrBtrim);
 
 	jspInitByBuffer(a, v->base, v->content.arg);
 }
@@ -1149,10 +1238,18 @@ jspGetNext(JsonPathItem *v, JsonPathItem *a)
 			   v->type == jpiInteger ||
 			   v->type == jpiNumber ||
 			   v->type == jpiStringFunc ||
+			   v->type == jpiStrReplace ||
+			   v->type == jpiStrLower ||
+			   v->type == jpiStrUpper ||
 			   v->type == jpiTime ||
 			   v->type == jpiTimeTz ||
 			   v->type == jpiTimestamp ||
-			   v->type == jpiTimestampTz);
+			   v->type == jpiTimestampTz ||
+			   v->type == jpiStrLtrim ||
+			   v->type == jpiStrRtrim ||
+			   v->type == jpiStrBtrim ||
+			   v->type == jpiStrInitcap ||
+			   v->type == jpiStrSplitPart);
 
 		if (a)
 			jspInitByBuffer(a, v->base, v->nextPos);
@@ -1201,7 +1298,9 @@ jspGetRightArg(JsonPathItem *v, JsonPathItem *a)
 		   v->type == jpiDiv ||
 		   v->type == jpiMod ||
 		   v->type == jpiStartsWith ||
-		   v->type == jpiDecimal);
+		   v->type == jpiDecimal ||
+		   v->type == jpiStrReplace ||
+		   v->type == jpiStrSplitPart);
 
 	jspInitByBuffer(a, v->base, v->content.args.right);
 }
@@ -1501,6 +1600,14 @@ jspIsMutableWalker(JsonPathItem *jpi, struct JsonPathMutableContext *cxt)
 			case jpiInteger:
 			case jpiNumber:
 			case jpiStringFunc:
+			case jpiStrReplace:
+			case jpiStrLower:
+			case jpiStrUpper:
+			case jpiStrLtrim:
+			case jpiStrRtrim:
+			case jpiStrBtrim:
+			case jpiStrInitcap:
+			case jpiStrSplitPart:
 				status = jpdsNonDateTime;
 				break;
 
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index dbab24737ef..28a04b24bfa 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -301,6 +301,8 @@ static JsonPathExecResult executeNumericItemMethod(JsonPathExecContext *cxt,
 												   JsonValueList *found);
 static JsonPathExecResult executeDateTimeMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
 												JsonbValue *jb, JsonValueList *found);
+static JsonPathExecResult executeStringInternalMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
+													  JsonbValue *jb, JsonValueList *found);
 static JsonPathExecResult executeKeyValueMethod(JsonPathExecContext *cxt,
 												JsonPathItem *jsp, JsonbValue *jb, JsonValueList *found);
 static JsonPathExecResult appendBoolResult(JsonPathExecContext *cxt,
@@ -1659,6 +1661,23 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
 			}
 			break;
 
+		case jpiStrLtrim:
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrReplace:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
+		case jpiStrInitcap:
+		case jpiStrSplitPart:
+			{
+				if (unwrap && JsonbType(jb) == jbvArray)
+					return executeItemUnwrapTargetArray(cxt, jsp, jb, found, false);
+
+				return executeStringInternalMethod(cxt, jsp, jb, found);
+			}
+			break;
+
+
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", jsp->type);
 	}
@@ -2792,6 +2811,193 @@ executeDateTimeMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
 	return executeNextItem(cxt, jsp, &elem, jb, found, hasNext);
 }
 
+/*
+ * Implementation of .upper(), lower() et. al. methods,
+ * that forward their actual implementation to internal functions.
+ */
+static JsonPathExecResult
+executeStringInternalMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
+							JsonbValue *jb, JsonValueList *found)
+{
+	Assert(jsp->type == jpiStrLower ||
+		   jsp->type == jpiStrUpper ||
+		   jsp->type == jpiStrReplace ||
+		   jsp->type == jpiStrLtrim ||
+		   jsp->type == jpiStrRtrim ||
+		   jsp->type == jpiStrBtrim ||
+		   jsp->type == jpiStrInitcap ||
+		   jsp->type == jpiStrSplitPart);
+	JsonbValue	jbvbuf;
+	bool		hasNext;
+	JsonPathExecResult res = jperNotFound;
+	JsonPathItem elem;
+	Datum		str;			/* Datum representation for the current string
+								 * value. The first argument to internal
+								 * functions */
+	char	   *tmp = NULL;
+	char	   *resStr = NULL;
+
+	if (!(jb = getScalar(jb, jbvString)))
+		RETURN_ERROR(ereport(ERROR,
+							 (errcode(ERRCODE_INVALID_ARGUMENT_FOR_SQL_JSON_DATETIME_FUNCTION),
+							  errmsg("jsonpath item method .%s() can only be applied to a string",
+									 jspOperationName(jsp->type)))));
+
+	tmp = pnstrdup(jb->val.string.val, jb->val.string.len);
+	str = CStringGetTextDatum(tmp);
+
+	/* Internal string functions that accept no arguments */
+	switch (jsp->type)
+	{
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
+			{
+				char	   *characters_str;
+				int			characters_len;
+				PGFunction	func = NULL;
+
+				if (jsp->content.arg)
+				{
+					switch (jsp->type)
+					{
+						case jpiStrLtrim:
+							func = ltrim;
+							break;
+						case jpiStrRtrim:
+							func = rtrim;
+							break;
+						case jpiStrBtrim:
+							func = btrim;
+							break;
+						default:;
+					}
+					jspGetArg(jsp, &elem);
+					if (elem.type != jpiString)
+						elog(ERROR, "invalid jsonpath item type for .%s() argument", jspOperationName(jsp->type));
+
+					characters_str = jspGetString(&elem, &characters_len);
+					resStr = TextDatumGetCString(DirectFunctionCall2Coll(func,
+																		 DEFAULT_COLLATION_OID, str,
+																		 CStringGetTextDatum(characters_str)));
+					break;
+				}
+
+				switch (jsp->type)
+				{
+					case jpiStrLtrim:
+						func = ltrim1;
+						break;
+					case jpiStrRtrim:
+						func = rtrim1;
+						break;
+					case jpiStrBtrim:
+						func = btrim1;
+						break;
+					default:;
+				}
+				resStr = TextDatumGetCString(DirectFunctionCall1Coll(func,
+																	 DEFAULT_COLLATION_OID, str));
+				break;
+			}
+
+		case jpiStrLower:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(lower, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiStrUpper:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(upper, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiStrInitcap:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(initcap, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiStrReplace:
+			{
+				char	   *from_str,
+						   *to_str;
+				int			from_len,
+							to_len;
+
+				jspGetLeftArg(jsp, &elem);
+				if (elem.type != jpiString)
+					elog(ERROR, "invalid jsonpath item type for .replace() from");
+
+				from_str = jspGetString(&elem, &from_len);
+
+				jspGetRightArg(jsp, &elem);
+				if (elem.type != jpiString)
+					elog(ERROR, "invalid jsonpath item type for .replace() to");
+
+				to_str = jspGetString(&elem, &to_len);
+
+				resStr = TextDatumGetCString(DirectFunctionCall3Coll(replace_text,
+																	 C_COLLATION_OID,
+																	 CStringGetTextDatum(tmp),
+																	 CStringGetTextDatum(from_str),
+																	 CStringGetTextDatum(to_str)));
+				break;
+			}
+		case jpiStrSplitPart:
+			{
+				char	   *from_str;
+				Numeric		n;
+				int			from_len;
+
+				jspGetLeftArg(jsp, &elem);
+				if (elem.type != jpiString)
+					elog(ERROR, "invalid jsonpath item type for .split_part()");
+
+				from_str = jspGetString(&elem, &from_len);
+
+				jspGetRightArg(jsp, &elem);
+				if (elem.type != jpiNumeric)
+					elog(ERROR, "invalid jsonpath item type for .split_part()");
+
+				n = jspGetNumeric(&elem);
+
+				resStr = TextDatumGetCString(DirectFunctionCall3Coll(split_part,
+																	 C_COLLATION_OID,
+																	 CStringGetTextDatum(tmp),
+																	 CStringGetTextDatum(from_str),
+																	 DirectFunctionCall1(numeric_int8, NumericGetDatum(n))));
+				break;
+			}
+		default:
+			elog(ERROR, "unsupported jsonpath item type: %d", jsp->type);
+	}
+
+	if (resStr)
+		res = jperOk;
+
+	hasNext = jspGetNext(jsp, &elem);
+
+	if (!hasNext && !found)
+		return res;
+
+	jb = hasNext ? &jbvbuf : palloc(sizeof(*jb));
+
+	/* Create the appropriate jb value to return */
+	switch (jsp->type)
+	{
+			/* Cases for functions that return text */
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrReplace:
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
+		case jpiStrInitcap:
+		case jpiStrSplitPart:
+			jb->type = jbvString;
+			jb->val.string.val = resStr;
+			jb->val.string.len = strlen(jb->val.string.val);
+		default:
+			;
+			/* cant' happen */
+	}
+
+	return executeNextItem(cxt, jsp, &elem, jb, found, hasNext);
+}
+
 /*
  * Implementation of .keyvalue() method.
  *
diff --git a/src/backend/utils/adt/jsonpath_gram.y b/src/backend/utils/adt/jsonpath_gram.y
index 0b16cec18c4..53bf779e152 100644
--- a/src/backend/utils/adt/jsonpath_gram.y
+++ b/src/backend/utils/adt/jsonpath_gram.y
@@ -86,6 +86,8 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 %token	<str>		DATETIME_P
 %token	<str>		BIGINT_P BOOLEAN_P DATE_P DECIMAL_P INTEGER_P NUMBER_P
 %token	<str>		STRINGFUNC_P TIME_P TIME_TZ_P TIMESTAMP_P TIMESTAMP_TZ_P
+%token	<str>		STR_REPLACE_P STR_LOWER_P STR_UPPER_P STR_LTRIM_P STR_RTRIM_P STR_BTRIM_P
+					STR_INITCAP_P STR_SPLIT_PART_P
 
 %type	<result>	result
 
@@ -95,7 +97,7 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 					str_elem opt_str_arg int_elem
 					uint_elem opt_uint_arg
 
-%type	<elems>		accessor_expr int_list opt_int_list
+%type	<elems>		accessor_expr int_list opt_int_list str_int_args str_str_args
 
 %type	<indexs>	index_list
 
@@ -278,6 +280,16 @@ accessor_op:
 		{ $$ = makeItemUnary(jpiTimestamp, $4); }
 	| '.' TIMESTAMP_TZ_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimestampTz, $4); }
+	| '.' STR_REPLACE_P '(' str_str_args ')'
+		{ $$ = makeItemBinary(jpiStrReplace, linitial($4), lsecond($4)); }
+	| '.' STR_SPLIT_PART_P '(' str_int_args ')'
+		{ $$ = makeItemBinary(jpiStrSplitPart, linitial($4), lsecond($4)); }
+	| '.' STR_LTRIM_P '(' opt_str_arg ')'
+		{ $$ = makeItemUnary(jpiStrLtrim, $4); }
+	| '.' STR_RTRIM_P '(' opt_str_arg ')'
+		{ $$ = makeItemUnary(jpiStrRtrim, $4); }
+	| '.' STR_BTRIM_P '(' opt_str_arg ')'
+		{ $$ = makeItemUnary(jpiStrBtrim, $4); }
 	;
 
 int_elem:
@@ -317,6 +329,14 @@ opt_str_arg:
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
+str_int_args:
+	str_elem ',' int_elem			{ $$ = list_make2($1, $3); }
+	;
+
+str_str_args:
+	str_elem ',' str_elem 			{ $$ = list_make2($1, $3); }
+	;
+
 key:
 	key_name						{ $$ = makeItemKey(&$1); }
 	;
@@ -357,6 +377,9 @@ key_name:
 	| TIME_TZ_P
 	| TIMESTAMP_P
 	| TIMESTAMP_TZ_P
+	| STR_LTRIM_P
+	| STR_RTRIM_P
+	| STR_BTRIM_P
 	;
 
 method:
@@ -373,6 +396,9 @@ method:
 	| INTEGER_P						{ $$ = jpiInteger; }
 	| NUMBER_P						{ $$ = jpiNumber; }
 	| STRINGFUNC_P					{ $$ = jpiStringFunc; }
+	| STR_LOWER_P					{ $$ = jpiStrLower; }
+	| STR_UPPER_P					{ $$ = jpiStrUpper; }
+	| STR_INITCAP_P					{ $$ = jpiStrInitcap; }
 	;
 %%
 
diff --git a/src/backend/utils/adt/jsonpath_scan.l b/src/backend/utils/adt/jsonpath_scan.l
index c7aab83eeb4..69c61f98500 100644
--- a/src/backend/utils/adt/jsonpath_scan.l
+++ b/src/backend/utils/adt/jsonpath_scan.l
@@ -413,8 +413,13 @@ static const JsonPathKeyword keywords[] = {
 	{4, true, TRUE_P, "true"},
 	{4, false, TYPE_P, "type"},
 	{4, false, WITH_P, "with"},
+	{5, false, STR_BTRIM_P, "btrim"},
 	{5, true, FALSE_P, "false"},
 	{5, false, FLOOR_P, "floor"},
+	{5, false, STR_LOWER_P, "lower"},
+	{5, false, STR_LTRIM_P, "ltrim"},
+	{5, false, STR_RTRIM_P, "rtrim"},
+	{5, false, STR_UPPER_P, "upper"},
 	{6, false, BIGINT_P, "bigint"},
 	{6, false, DOUBLE_P, "double"},
 	{6, false, EXISTS_P, "exists"},
@@ -425,13 +430,16 @@ static const JsonPathKeyword keywords[] = {
 	{7, false, BOOLEAN_P, "boolean"},
 	{7, false, CEILING_P, "ceiling"},
 	{7, false, DECIMAL_P, "decimal"},
+	{7, false, STR_INITCAP_P, "initcap"},
 	{7, false, INTEGER_P, "integer"},
+	{7, false, STR_REPLACE_P, "replace"},
 	{7, false, TIME_TZ_P, "time_tz"},
 	{7, false, UNKNOWN_P, "unknown"},
 	{8, false, DATETIME_P, "datetime"},
 	{8, false, KEYVALUE_P, "keyvalue"},
 	{9, false, TIMESTAMP_P, "timestamp"},
 	{10, false, LIKE_REGEX_P, "like_regex"},
+	{10,false, STR_SPLIT_PART_P, "split_part"},
 	{12, false, TIMESTAMP_TZ_P, "timestamp_tz"},
 };
 
diff --git a/src/include/utils/jsonpath.h b/src/include/utils/jsonpath.h
index 23a76d233e9..2d0c53f7b06 100644
--- a/src/include/utils/jsonpath.h
+++ b/src/include/utils/jsonpath.h
@@ -115,6 +115,14 @@ typedef enum JsonPathItemType
 	jpiTimeTz,					/* .time_tz() item method */
 	jpiTimestamp,				/* .timestamp() item method */
 	jpiTimestampTz,				/* .timestamp_tz() item method */
+	jpiStrReplace,				/* .replace() item method */
+	jpiStrLower,				/* .lower() item method */
+	jpiStrUpper,				/* .upper() item method */
+	jpiStrLtrim,				/* .ltrim() item method */
+	jpiStrRtrim,				/* .rtrim() item method */
+	jpiStrBtrim,				/* .btrim() item method */
+	jpiStrInitcap,				/* .initcap() item method */
+	jpiStrSplitPart,			/* .split_part() item method */
 } JsonPathItemType;
 
 /* XQuery regex mode flags for LIKE_REGEX predicate */
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e91a29..cea539717f9 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -2723,6 +2723,405 @@ select jsonb_path_query('"2023-08-15 12:34:56"', '$.timestamp().string()');
 (1 row)
 
 rollback;
+-- test .ltrim()
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"zzzytest"', '$.ltrim("xyz")');
+ jsonb_path_query 
+------------------
+ "test"
+(1 row)
+
+select jsonb_path_query('null', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('null', '$.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.ltrim()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('{}', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('true', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('1234', '$.ltrim().type()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim()');
+  jsonb_path_query_array  
+--------------------------
+ ["maybe  ", "yes", "no"]
+(1 row)
+
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .rtrim()
+select jsonb_path_query('"   hello   "', '$.rtrim(" ")');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+select jsonb_path_query('"testxxzx"', '$.rtrim("xyz")');
+ jsonb_path_query 
+------------------
+ "test"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+-- test .btrim()
+select jsonb_path_query('"   hello   "', '$.btrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+select jsonb_path_query('"xyxtrimyyx"', '$.btrim("xyz")');
+ jsonb_path_query 
+------------------
+ "trim"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.btrim()');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.btrim()');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+-- test .lower()
+select jsonb_path_query('null', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('null', '$.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.lower()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('{}', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.lower()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.lower()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('true', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('1234', '$.lower().type()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower()');
+ jsonb_path_query_array 
+------------------------
+ ["maybe", "yes", "no"]
+(1 row)
+
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .upper()
+select jsonb_path_query('null', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('null', '$.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.upper()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('{}', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.upper()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.upper()');
+ jsonb_path_query 
+------------------
+ "1.23AAA"
+(1 row)
+
+select jsonb_path_query('1234', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('true', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('1234', '$.upper().type()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper()');
+ jsonb_path_query_array 
+------------------------
+ ["MAYBE", "YES", "NO"]
+(1 row)
+
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .initcap()
+select jsonb_path_query('null', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('null', '$.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.initcap()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('{}', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('true', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('1234', '$.initcap().type()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('["maybe yes", "probably no"]', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "Maybe Yes"
+ "Probably No"
+(2 rows)
+
+-- Test .replace()
+select jsonb_path_query('null', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('null', '$.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('["x", "y", "z"]', '$.replace("x", "bye")');
+ jsonb_path_query 
+------------------
+ "bye"
+ "y"
+ "z"
+(3 rows)
+
+select jsonb_path_query('{}', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('"hello world"', '$.replace("hello","bye")');
+ jsonb_path_query 
+------------------
+ "bye world"
+(1 row)
+
+select jsonb_path_query('"hello world"', '$.replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
+-- Test .split_part()
+select jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)');
+ jsonb_path_query 
+------------------
+ "def"
+(1 row)
+
+select jsonb_path_query('"abc,def,ghi,jkl"', '$.split_part(",", -2)');
+ jsonb_path_query 
+------------------
+ "ghi"
+(1 row)
+
+-- Test string methods play nicely together
+select jsonb_path_query('"hello world"', '$.replace("hello","bye").upper()');
+ jsonb_path_query 
+------------------
+ "BYE WORLD"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye")');
+ jsonb_path_query 
+------------------
+ "bye world"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.upper().lower().upper().replace("HELLO", "BYE")');
+ jsonb_path_query 
+------------------
+ "BYE WORLD"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
+select jsonb_path_query('"   hElLo WorlD "', '$.btrim().lower().upper().lower().replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
 -- Test .time()
 select jsonb_path_query('null', '$.time()');
 ERROR:  jsonpath item method .time() can only be applied to a string
diff --git a/src/test/regress/expected/jsonpath.out b/src/test/regress/expected/jsonpath.out
index fd9bd755f52..a13022feabd 100644
--- a/src/test/regress/expected/jsonpath.out
+++ b/src/test/regress/expected/jsonpath.out
@@ -435,6 +435,143 @@ select '$.string()'::jsonpath;
  $.string()
 (1 row)
 
+select '$.replace("hello","bye")'::jsonpath;
+         jsonpath         
+--------------------------
+ $.replace("hello","bye")
+(1 row)
+
+select '$.lower()'::jsonpath;
+ jsonpath  
+-----------
+ $.lower()
+(1 row)
+
+select '$.upper()'::jsonpath;
+ jsonpath  
+-----------
+ $.upper()
+(1 row)
+
+select '$.lower().upper().lower().replace("hello","bye")'::jsonpath;
+                     jsonpath                     
+--------------------------------------------------
+ $.lower().upper().lower().replace("hello","bye")
+(1 row)
+
+select '$.ltrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.ltrim()
+(1 row)
+
+select '$.ltrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.ltrim("xyz")
+(1 row)
+
+select '$.rtrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.rtrim()
+(1 row)
+
+select '$.rtrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.rtrim("xyz")
+(1 row)
+
+select '$.btrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.btrim()
+(1 row)
+
+select '$.btrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.btrim("xyz")
+(1 row)
+
+select '$.initcap()'::jsonpath;
+  jsonpath   
+-------------
+ $.initcap()
+(1 row)
+
+select '$.split_part("~@~", 2)'::jsonpath;
+       jsonpath        
+-----------------------
+ $.split_part("~@~",2)
+(1 row)
+
+-- Parse errors
+select '$.replace("hello")'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.replace("hello")'::jsonpath;
+               ^
+select '$.replace()'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.replace()'::jsonpath;
+               ^
+select '$.replace("hello","bye","extra")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.replace("hello","bye","extra")'::jsonpath;
+               ^
+select '$.split_part("~@~")'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.split_part("~@~")'::jsonpath;
+               ^
+select '$.split_part()'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.split_part()'::jsonpath;
+               ^
+select '$.split_part("~@~", "hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.split_part("~@~", "hi")'::jsonpath;
+               ^
+select '$.split_part("~@~", 2, "extra")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.split_part("~@~", 2, "extra")'::jsonpath;
+               ^
+select '$.lower("hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.lower("hi")'::jsonpath;
+               ^
+select '$.upper("hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.upper("hi")'::jsonpath;
+               ^
+select '$.initcap("hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.initcap("hi")'::jsonpath;
+               ^
+select '$.ltrim(42)'::jsonpath;
+ERROR:  syntax error at or near "42" of jsonpath input
+LINE 1: select '$.ltrim(42)'::jsonpath;
+               ^
+select '$.ltrim("x", "y")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.ltrim("x", "y")'::jsonpath;
+               ^
+select '$.rtrim(42)'::jsonpath;
+ERROR:  syntax error at or near "42" of jsonpath input
+LINE 1: select '$.rtrim(42)'::jsonpath;
+               ^
+select '$.rtrim("x", "y")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.rtrim("x", "y")'::jsonpath;
+               ^
+select '$.trim(42)'::jsonpath;
+ERROR:  syntax error at or near "(" of jsonpath input
+LINE 1: select '$.trim(42)'::jsonpath;
+               ^
+select '$.trim("x", "y")'::jsonpath;
+ERROR:  syntax error at or near "(" of jsonpath input
+LINE 1: select '$.trim("x", "y")'::jsonpath;
+               ^
 select '$.time()'::jsonpath;
  jsonpath 
 ----------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a5269..8169719343e 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -623,6 +623,115 @@ select jsonb_path_query('"2023-08-15 12:34:56 +5:30"', '$.timestamp_tz().string(
 select jsonb_path_query('"2023-08-15 12:34:56"', '$.timestamp().string()');
 rollback;
 
+-- test .ltrim()
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+select jsonb_path_query('"   hello   "', '$.ltrim()');
+select jsonb_path_query('"zzzytest"', '$.ltrim("xyz")');
+select jsonb_path_query('null', '$.ltrim()');
+select jsonb_path_query('null', '$.ltrim()', silent => true);
+select jsonb_path_query('[]', '$.ltrim()');
+select jsonb_path_query('[]', 'strict $.ltrim()');
+select jsonb_path_query('{}', '$.ltrim()');
+select jsonb_path_query('[]', 'strict $.ltrim()', silent => true);
+select jsonb_path_query('{}', '$.ltrim()', silent => true);
+select jsonb_path_query('1.23', '$.ltrim()');
+select jsonb_path_query('"1.23"', '$.ltrim()');
+select jsonb_path_query('"1.23aaa"', '$.ltrim()');
+select jsonb_path_query('1234', '$.ltrim()');
+select jsonb_path_query('true', '$.ltrim()');
+select jsonb_path_query('1234', '$.ltrim().type()');
+select jsonb_path_query('[2, true]', '$.ltrim()');
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim()');
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim().type()');
+
+-- test .rtrim()
+select jsonb_path_query('"   hello   "', '$.rtrim(" ")');
+select jsonb_path_query('"testxxzx"', '$.rtrim("xyz")');
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+
+-- test .btrim()
+select jsonb_path_query('"   hello   "', '$.btrim(" ")');
+select jsonb_path_query('"xyxtrimyyx"', '$.btrim("xyz")');
+select jsonb_path_query('"   hello   "', '$.btrim()');
+select jsonb_path_query('"   hello   "', '$.btrim()');
+
+-- test .lower()
+select jsonb_path_query('null', '$.lower()');
+select jsonb_path_query('null', '$.lower()', silent => true);
+select jsonb_path_query('[]', '$.lower()');
+select jsonb_path_query('[]', 'strict $.lower()');
+select jsonb_path_query('{}', '$.lower()');
+select jsonb_path_query('[]', 'strict $.lower()', silent => true);
+select jsonb_path_query('{}', '$.lower()', silent => true);
+select jsonb_path_query('1.23', '$.lower()');
+select jsonb_path_query('"1.23"', '$.lower()');
+select jsonb_path_query('"1.23aaa"', '$.lower()');
+select jsonb_path_query('1234', '$.lower()');
+select jsonb_path_query('true', '$.lower()');
+select jsonb_path_query('1234', '$.lower().type()');
+select jsonb_path_query('[2, true]', '$.lower()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower().type()');
+
+-- test .upper()
+select jsonb_path_query('null', '$.upper()');
+select jsonb_path_query('null', '$.upper()', silent => true);
+select jsonb_path_query('[]', '$.upper()');
+select jsonb_path_query('[]', 'strict $.upper()');
+select jsonb_path_query('{}', '$.upper()');
+select jsonb_path_query('[]', 'strict $.upper()', silent => true);
+select jsonb_path_query('{}', '$.upper()', silent => true);
+select jsonb_path_query('1.23', '$.upper()');
+select jsonb_path_query('"1.23"', '$.upper()');
+select jsonb_path_query('"1.23aaa"', '$.upper()');
+select jsonb_path_query('1234', '$.upper()');
+select jsonb_path_query('true', '$.upper()');
+select jsonb_path_query('1234', '$.upper().type()');
+select jsonb_path_query('[2, true]', '$.upper()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper().type()');
+
+-- test .initcap()
+select jsonb_path_query('null', '$.initcap()');
+select jsonb_path_query('null', '$.initcap()', silent => true);
+select jsonb_path_query('[]', '$.initcap()');
+select jsonb_path_query('[]', 'strict $.initcap()');
+select jsonb_path_query('{}', '$.initcap()');
+select jsonb_path_query('[]', 'strict $.initcap()', silent => true);
+select jsonb_path_query('{}', '$.initcap()', silent => true);
+select jsonb_path_query('1.23', '$.initcap()');
+select jsonb_path_query('"1.23"', '$.initcap()');
+select jsonb_path_query('"1.23aaa"', '$.initcap()');
+select jsonb_path_query('1234', '$.initcap()');
+select jsonb_path_query('true', '$.initcap()');
+select jsonb_path_query('1234', '$.initcap().type()');
+select jsonb_path_query('[2, true]', '$.initcap()');
+select jsonb_path_query('["maybe yes", "probably no"]', '$.initcap()');
+
+-- Test .replace()
+select jsonb_path_query('null', '$.replace("x", "bye")');
+select jsonb_path_query('null', '$.replace("x", "bye")', silent => true);
+select jsonb_path_query('["x", "y", "z"]', '$.replace("x", "bye")');
+select jsonb_path_query('{}', '$.replace("x", "bye")');
+select jsonb_path_query('[]', 'strict $.replace("x", "bye")', silent => true);
+select jsonb_path_query('{}', '$.replace("x", "bye")', silent => true);
+select jsonb_path_query('1.23', '$.replace("x", "bye")');
+select jsonb_path_query('"hello world"', '$.replace("hello","bye")');
+select jsonb_path_query('"hello world"', '$.replace("hello","bye") starts with "bye"');
+
+-- Test .split_part()
+select jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)');
+select jsonb_path_query('"abc,def,ghi,jkl"', '$.split_part(",", -2)');
+
+-- Test string methods play nicely together
+select jsonb_path_query('"hello world"', '$.replace("hello","bye").upper()');
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye")');
+select jsonb_path_query('"hElLo WorlD"', '$.upper().lower().upper().replace("HELLO", "BYE")');
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye") starts with "bye"');
+select jsonb_path_query('"   hElLo WorlD "', '$.btrim().lower().upper().lower().replace("hello","bye") starts with "bye"');
+
 -- Test .time()
 select jsonb_path_query('null', '$.time()');
 select jsonb_path_query('true', '$.time()');
diff --git a/src/test/regress/sql/jsonpath.sql b/src/test/regress/sql/jsonpath.sql
index 61a5270d4e8..7dd2e57e7a6 100644
--- a/src/test/regress/sql/jsonpath.sql
+++ b/src/test/regress/sql/jsonpath.sql
@@ -78,6 +78,37 @@ select '$.boolean()'::jsonpath;
 select '$.date()'::jsonpath;
 select '$.decimal(4,2)'::jsonpath;
 select '$.string()'::jsonpath;
+select '$.replace("hello","bye")'::jsonpath;
+select '$.lower()'::jsonpath;
+select '$.upper()'::jsonpath;
+select '$.lower().upper().lower().replace("hello","bye")'::jsonpath;
+select '$.ltrim()'::jsonpath;
+select '$.ltrim("xyz")'::jsonpath;
+select '$.rtrim()'::jsonpath;
+select '$.rtrim("xyz")'::jsonpath;
+select '$.btrim()'::jsonpath;
+select '$.btrim("xyz")'::jsonpath;
+select '$.initcap()'::jsonpath;
+select '$.split_part("~@~", 2)'::jsonpath;
+
+-- Parse errors
+select '$.replace("hello")'::jsonpath;
+select '$.replace()'::jsonpath;
+select '$.replace("hello","bye","extra")'::jsonpath;
+select '$.split_part("~@~")'::jsonpath;
+select '$.split_part()'::jsonpath;
+select '$.split_part("~@~", "hi")'::jsonpath;
+select '$.split_part("~@~", 2, "extra")'::jsonpath;
+select '$.lower("hi")'::jsonpath;
+select '$.upper("hi")'::jsonpath;
+select '$.initcap("hi")'::jsonpath;
+select '$.ltrim(42)'::jsonpath;
+select '$.ltrim("x", "y")'::jsonpath;
+select '$.rtrim(42)'::jsonpath;
+select '$.rtrim("x", "y")'::jsonpath;
+select '$.trim(42)'::jsonpath;
+select '$.trim("x", "y")'::jsonpath;
+
 select '$.time()'::jsonpath;
 select '$.time(6)'::jsonpath;
 select '$.time_tz()'::jsonpath;
-- 
2.49.0

From 11c3b981fbf80eaa6f21130b2e9e59df4855df2c Mon Sep 17 00:00:00 2001
From: "David E. Wheeler" <david@justatheory.com>
Date: Mon, 2 Jun 2025 17:14:10 -0400
Subject: [PATCH v9 1/2] Rename jsonpath method arg tokens

Rename the `csv_` tokens to `int_`, because they represent signed or
unsigned integers, as follows:

*   `csv_elem` => `int_elem`
*   `csv_list` => `int_list`
*   `opt_csv_list` => `opt_int_list`

Rename the `datetime_precision` tokens to `uint_arg`, as they represent
unsigned integers and will be useful for other methods in the future, as
follows:

*   `datetime_precision` => `uint_elem`
*   `opt_datetime_precision` => `opt_uint_arg`

Rename the `datetime_template` tokens to `str_arg`, as they represent
strings and will be useful for other methods in the future, as follows:

*   `datetime_template` => `str_elem`
*   `opt_datetime_template` => `opt_str_arg`
---
 src/backend/utils/adt/jsonpath_gram.y | 42 +++++++++++++--------------
 1 file changed, 21 insertions(+), 21 deletions(-)

diff --git a/src/backend/utils/adt/jsonpath_gram.y b/src/backend/utils/adt/jsonpath_gram.y
index 499745a8fef..0b16cec18c4 100644
--- a/src/backend/utils/adt/jsonpath_gram.y
+++ b/src/backend/utils/adt/jsonpath_gram.y
@@ -92,10 +92,10 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 %type	<value>		scalar_value path_primary expr array_accessor
 					any_path accessor_op key predicate delimited_predicate
 					index_elem starts_with_initial expr_or_predicate
-					datetime_template opt_datetime_template csv_elem
-					datetime_precision opt_datetime_precision
+					str_elem opt_str_arg int_elem
+					uint_elem opt_uint_arg
 
-%type	<elems>		accessor_expr csv_list opt_csv_list
+%type	<elems>		accessor_expr int_list opt_int_list
 
 %type	<indexs>	index_list
 
@@ -254,7 +254,7 @@ accessor_op:
 	| '.' any_path					{ $$ = $2; }
 	| '.' method '(' ')'			{ $$ = makeItemType($2); }
 	| '?' '(' predicate ')'			{ $$ = makeItemUnary(jpiFilter, $3); }
-	| '.' DECIMAL_P '(' opt_csv_list ')'
+	| '.' DECIMAL_P '(' opt_int_list ')'
 		{
 			if (list_length($4) == 0)
 				$$ = makeItemBinary(jpiDecimal, NULL, NULL);
@@ -268,19 +268,19 @@ accessor_op:
 						 errmsg("invalid input syntax for type %s", "jsonpath"),
 						 errdetail(".decimal() can only have an optional precision[,scale].")));
 		}
-	| '.' DATETIME_P '(' opt_datetime_template ')'
+	| '.' DATETIME_P '(' opt_str_arg ')'
 		{ $$ = makeItemUnary(jpiDatetime, $4); }
-	| '.' TIME_P '(' opt_datetime_precision ')'
+	| '.' TIME_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTime, $4); }
-	| '.' TIME_TZ_P '(' opt_datetime_precision ')'
+	| '.' TIME_TZ_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimeTz, $4); }
-	| '.' TIMESTAMP_P '(' opt_datetime_precision ')'
+	| '.' TIMESTAMP_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimestamp, $4); }
-	| '.' TIMESTAMP_TZ_P '(' opt_datetime_precision ')'
+	| '.' TIMESTAMP_TZ_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimestampTz, $4); }
 	;
 
-csv_elem:
+int_elem:
 	INT_P
 		{ $$ = makeItemNumeric(&$1); }
 	| '+' INT_P %prec UMINUS
@@ -289,31 +289,31 @@ csv_elem:
 		{ $$ = makeItemUnary(jpiMinus, makeItemNumeric(&$2)); }
 	;
 
-csv_list:
-	csv_elem						{ $$ = list_make1($1); }
-	| csv_list ',' csv_elem			{ $$ = lappend($1, $3); }
+int_list:
+	int_elem						{ $$ = list_make1($1); }
+	| int_list ',' int_elem			{ $$ = lappend($1, $3); }
 	;
 
-opt_csv_list:
-	csv_list						{ $$ = $1; }
+opt_int_list:
+	int_list						{ $$ = $1; }
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
-datetime_precision:
+uint_elem:
 	INT_P							{ $$ = makeItemNumeric(&$1); }
 	;
 
-opt_datetime_precision:
-	datetime_precision				{ $$ = $1; }
+opt_uint_arg:
+	uint_elem						{ $$ = $1; }
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
-datetime_template:
+str_elem:
 	STRING_P						{ $$ = makeItemString(&$1); }
 	;
 
-opt_datetime_template:
-	datetime_template				{ $$ = $1; }
+opt_str_arg:
+	str_elem						{ $$ = $1; }
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
-- 
2.49.0

From ea19345548e215aedff6ef03274a2455b56a05ad Mon Sep 17 00:00:00 2001
From: Florents Tselai <florents.tselai@gmail.com>
Date: Wed, 4 Jun 2025 11:21:23 -0400
Subject: [PATCH v9 2/2] Add additional jsonpath string methods

Add the following jsonpath methods:

*   l/r/btrim()
*   lower(), upper()
*   initcap()
*   replace()
*   split_part()

Each simply dispatches to the standard string processing functions.
These depend on the locale, but since it's set at `initdb`, they can be
considered immutable and therefore allowed in any jsonpath expression.
---
 doc/src/sgml/func.sgml                       | 140 +++++++
 src/backend/utils/adt/jsonpath.c             | 113 +++++-
 src/backend/utils/adt/jsonpath_exec.c        | 206 ++++++++++
 src/backend/utils/adt/jsonpath_gram.y        |  28 +-
 src/backend/utils/adt/jsonpath_scan.l        |   8 +
 src/include/utils/jsonpath.h                 |   8 +
 src/test/regress/expected/jsonb_jsonpath.out | 399 +++++++++++++++++++
 src/test/regress/expected/jsonpath.out       | 137 +++++++
 src/test/regress/sql/jsonb_jsonpath.sql      | 109 +++++
 src/test/regress/sql/jsonpath.sql            |  31 ++
 10 files changed, 1175 insertions(+), 4 deletions(-)

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index c67688cbf5f..674c22c78d8 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -18627,6 +18627,146 @@ ERROR:  jsonpath member accessor can only be applied to an object
         <returnvalue>[{"id": 0, "key": "x", "value": "20"}, {"id": 0, "key": "y", "value": 32}]</returnvalue>
        </para></entry>
       </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>lower()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String converted to all lower case according to the rules of the database's locale.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"TOM"', '$.lower()')</literal>
+        <returnvalue>"tom"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>upper()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String converted to all upper case according to the rules of the database's locale.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"tom"', '$.upper()')</literal>
+        <returnvalue>"TOM"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>initcap()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the first letter of each word converted to upper case
+        according to the rules of the database's locale. Words are sequences
+        of alphanumeric characters separated by non-alphanumeric characters.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"hi THOMAS"', '$.initcap()')</literal>
+        <returnvalue>"Hi Thomas"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>replace(<replaceable>from</replaceable>, <replaceable>to</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with all occurrences of substring from replaced with substring to.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"abcdefabcdef"', '$.replace("cd", "XX")')</literal>
+        <returnvalue>"abXXefabXXef"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>split_part(<replaceable>delimiter</replaceable>, <replaceable>n</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String split at occurrences of <replaceable>delimiter</replaceable>
+        and returns the <replaceable>n</replaceable>'th field (counting from
+        one) or, when <replaceable>n</replaceable> is negative, returns the
+        |<replaceable>n</replaceable>|'th-from-last field.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)')</literal>
+        <returnvalue>"def"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"abc,def,ghi,jkl"', '$.split_part(",", 2)')</literal>
+        <returnvalue>"ghi"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>ltrim(<replaceable>characters</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the longest string containing only spaces or the
+        characters in <replaceable>characters</replaceable> removed from the
+        start of <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal> jsonb_path_query('"  hello"', '$.ltrim()')</literal>
+        <returnvalue>"hello"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"zzzytest"', '$.ltrim("xyz")')</literal>
+        <returnvalue>"test"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>rtrim([ <replaceable>characters</replaceable> ])</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the longest string containing only spaces or the
+        characters in <replaceable>characters</replaceable> removed from the
+        end of <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"hello  "', '$.rtrim()')</literal>
+        <returnvalue>"hello"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"testxxzx"', '$.rtrim("xyz")')</literal>
+        <returnvalue>"test"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>btrim([ <replaceable>characters</replaceable> ])</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the longest string containing only spaces or the
+        characters in <replaceable>characters</replaceable> removed from the
+        start and end of <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"  hello  "', '$.btrim()')</literal>
+        <returnvalue>"hello"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"xyxtrimyyx"', '$.btrim("xyz")')</literal>
+        <returnvalue>"trim"</returnvalue>
+       </para></entry>
+      </row>
+
      </tbody>
     </tgroup>
    </table>
diff --git a/src/backend/utils/adt/jsonpath.c b/src/backend/utils/adt/jsonpath.c
index 762f7e8a09d..0872b115697 100644
--- a/src/backend/utils/adt/jsonpath.c
+++ b/src/backend/utils/adt/jsonpath.c
@@ -298,6 +298,8 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 		case jpiMod:
 		case jpiStartsWith:
 		case jpiDecimal:
+		case jpiStrReplace:
+		case jpiStrSplitPart:
 			{
 				/*
 				 * First, reserve place for left/right arg's positions, then
@@ -362,6 +364,9 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 		case jpiTimeTz:
 		case jpiTimestamp:
 		case jpiTimestampTz:
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
 			{
 				int32		arg = reserveSpaceForItemPointer(buf);
 
@@ -457,6 +462,9 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 		case jpiInteger:
 		case jpiNumber:
 		case jpiStringFunc:
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrInitcap:
 			break;
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", item->type);
@@ -831,6 +839,60 @@ printJsonPathItem(StringInfo buf, JsonPathItem *v, bool inKey,
 			}
 			appendStringInfoChar(buf, ')');
 			break;
+		case jpiStrReplace:
+			appendStringInfoString(buf, ".replace(");
+			jspGetLeftArg(v, &elem);
+			printJsonPathItem(buf, &elem, false, false);
+			appendStringInfoChar(buf, ',');
+			jspGetRightArg(v, &elem);
+			printJsonPathItem(buf, &elem, false, false);
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrSplitPart:
+			appendStringInfoString(buf, ".split_part(");
+			jspGetLeftArg(v, &elem);
+			printJsonPathItem(buf, &elem, false, false);
+			appendStringInfoChar(buf, ',');
+			jspGetRightArg(v, &elem);
+			printJsonPathItem(buf, &elem, false, false);
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrLower:
+			appendStringInfoString(buf, ".lower()");
+			break;
+		case jpiStrUpper:
+			appendStringInfoString(buf, ".upper()");
+			break;
+		case jpiStrInitcap:
+			appendStringInfoString(buf, ".initcap()");
+			break;
+		case jpiStrLtrim:
+			appendStringInfoString(buf, ".ltrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrRtrim:
+			appendStringInfoString(buf, ".rtrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrBtrim:
+			appendStringInfoString(buf, ".btrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", v->type);
 	}
@@ -906,6 +968,12 @@ jspOperationName(JsonPathItemType type)
 			return "number";
 		case jpiStringFunc:
 			return "string";
+		case jpiStrReplace:
+			return "replace";
+		case jpiStrLower:
+			return "lower";
+		case jpiStrUpper:
+			return "upper";
 		case jpiTime:
 			return "time";
 		case jpiTimeTz:
@@ -914,6 +982,16 @@ jspOperationName(JsonPathItemType type)
 			return "timestamp";
 		case jpiTimestampTz:
 			return "timestamp_tz";
+		case jpiStrLtrim:
+			return "ltrim";
+		case jpiStrRtrim:
+			return "rtrim";
+		case jpiStrBtrim:
+			return "btrim";
+		case jpiStrInitcap:
+			return "initcap";
+		case jpiStrSplitPart:
+			return "split_part";
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", type);
 			return NULL;
@@ -1016,6 +1094,9 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 		case jpiInteger:
 		case jpiNumber:
 		case jpiStringFunc:
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrInitcap:
 			break;
 		case jpiString:
 		case jpiKey:
@@ -1041,6 +1122,8 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 		case jpiMod:
 		case jpiStartsWith:
 		case jpiDecimal:
+		case jpiStrReplace:
+		case jpiStrSplitPart:
 			read_int32(v->content.args.left, base, pos);
 			read_int32(v->content.args.right, base, pos);
 			break;
@@ -1055,6 +1138,9 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 		case jpiTimeTz:
 		case jpiTimestamp:
 		case jpiTimestampTz:
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
 			read_int32(v->content.arg, base, pos);
 			break;
 		case jpiIndexArray:
@@ -1090,7 +1176,10 @@ jspGetArg(JsonPathItem *v, JsonPathItem *a)
 		   v->type == jpiTime ||
 		   v->type == jpiTimeTz ||
 		   v->type == jpiTimestamp ||
-		   v->type == jpiTimestampTz);
+		   v->type == jpiTimestampTz ||
+		   v->type == jpiStrLtrim ||
+		   v->type == jpiStrRtrim ||
+		   v->type == jpiStrBtrim);
 
 	jspInitByBuffer(a, v->base, v->content.arg);
 }
@@ -1149,10 +1238,18 @@ jspGetNext(JsonPathItem *v, JsonPathItem *a)
 			   v->type == jpiInteger ||
 			   v->type == jpiNumber ||
 			   v->type == jpiStringFunc ||
+			   v->type == jpiStrReplace ||
+			   v->type == jpiStrLower ||
+			   v->type == jpiStrUpper ||
 			   v->type == jpiTime ||
 			   v->type == jpiTimeTz ||
 			   v->type == jpiTimestamp ||
-			   v->type == jpiTimestampTz);
+			   v->type == jpiTimestampTz ||
+			   v->type == jpiStrLtrim ||
+			   v->type == jpiStrRtrim ||
+			   v->type == jpiStrBtrim ||
+			   v->type == jpiStrInitcap ||
+			   v->type == jpiStrSplitPart);
 
 		if (a)
 			jspInitByBuffer(a, v->base, v->nextPos);
@@ -1201,7 +1298,9 @@ jspGetRightArg(JsonPathItem *v, JsonPathItem *a)
 		   v->type == jpiDiv ||
 		   v->type == jpiMod ||
 		   v->type == jpiStartsWith ||
-		   v->type == jpiDecimal);
+		   v->type == jpiDecimal ||
+		   v->type == jpiStrReplace ||
+		   v->type == jpiStrSplitPart);
 
 	jspInitByBuffer(a, v->base, v->content.args.right);
 }
@@ -1501,6 +1600,14 @@ jspIsMutableWalker(JsonPathItem *jpi, struct JsonPathMutableContext *cxt)
 			case jpiInteger:
 			case jpiNumber:
 			case jpiStringFunc:
+			case jpiStrReplace:
+			case jpiStrLower:
+			case jpiStrUpper:
+			case jpiStrLtrim:
+			case jpiStrRtrim:
+			case jpiStrBtrim:
+			case jpiStrInitcap:
+			case jpiStrSplitPart:
 				status = jpdsNonDateTime;
 				break;
 
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index dbab24737ef..28a04b24bfa 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -301,6 +301,8 @@ static JsonPathExecResult executeNumericItemMethod(JsonPathExecContext *cxt,
 												   JsonValueList *found);
 static JsonPathExecResult executeDateTimeMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
 												JsonbValue *jb, JsonValueList *found);
+static JsonPathExecResult executeStringInternalMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
+													  JsonbValue *jb, JsonValueList *found);
 static JsonPathExecResult executeKeyValueMethod(JsonPathExecContext *cxt,
 												JsonPathItem *jsp, JsonbValue *jb, JsonValueList *found);
 static JsonPathExecResult appendBoolResult(JsonPathExecContext *cxt,
@@ -1659,6 +1661,23 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
 			}
 			break;
 
+		case jpiStrLtrim:
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrReplace:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
+		case jpiStrInitcap:
+		case jpiStrSplitPart:
+			{
+				if (unwrap && JsonbType(jb) == jbvArray)
+					return executeItemUnwrapTargetArray(cxt, jsp, jb, found, false);
+
+				return executeStringInternalMethod(cxt, jsp, jb, found);
+			}
+			break;
+
+
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", jsp->type);
 	}
@@ -2792,6 +2811,193 @@ executeDateTimeMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
 	return executeNextItem(cxt, jsp, &elem, jb, found, hasNext);
 }
 
+/*
+ * Implementation of .upper(), lower() et. al. methods,
+ * that forward their actual implementation to internal functions.
+ */
+static JsonPathExecResult
+executeStringInternalMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
+							JsonbValue *jb, JsonValueList *found)
+{
+	Assert(jsp->type == jpiStrLower ||
+		   jsp->type == jpiStrUpper ||
+		   jsp->type == jpiStrReplace ||
+		   jsp->type == jpiStrLtrim ||
+		   jsp->type == jpiStrRtrim ||
+		   jsp->type == jpiStrBtrim ||
+		   jsp->type == jpiStrInitcap ||
+		   jsp->type == jpiStrSplitPart);
+	JsonbValue	jbvbuf;
+	bool		hasNext;
+	JsonPathExecResult res = jperNotFound;
+	JsonPathItem elem;
+	Datum		str;			/* Datum representation for the current string
+								 * value. The first argument to internal
+								 * functions */
+	char	   *tmp = NULL;
+	char	   *resStr = NULL;
+
+	if (!(jb = getScalar(jb, jbvString)))
+		RETURN_ERROR(ereport(ERROR,
+							 (errcode(ERRCODE_INVALID_ARGUMENT_FOR_SQL_JSON_DATETIME_FUNCTION),
+							  errmsg("jsonpath item method .%s() can only be applied to a string",
+									 jspOperationName(jsp->type)))));
+
+	tmp = pnstrdup(jb->val.string.val, jb->val.string.len);
+	str = CStringGetTextDatum(tmp);
+
+	/* Internal string functions that accept no arguments */
+	switch (jsp->type)
+	{
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
+			{
+				char	   *characters_str;
+				int			characters_len;
+				PGFunction	func = NULL;
+
+				if (jsp->content.arg)
+				{
+					switch (jsp->type)
+					{
+						case jpiStrLtrim:
+							func = ltrim;
+							break;
+						case jpiStrRtrim:
+							func = rtrim;
+							break;
+						case jpiStrBtrim:
+							func = btrim;
+							break;
+						default:;
+					}
+					jspGetArg(jsp, &elem);
+					if (elem.type != jpiString)
+						elog(ERROR, "invalid jsonpath item type for .%s() argument", jspOperationName(jsp->type));
+
+					characters_str = jspGetString(&elem, &characters_len);
+					resStr = TextDatumGetCString(DirectFunctionCall2Coll(func,
+																		 DEFAULT_COLLATION_OID, str,
+																		 CStringGetTextDatum(characters_str)));
+					break;
+				}
+
+				switch (jsp->type)
+				{
+					case jpiStrLtrim:
+						func = ltrim1;
+						break;
+					case jpiStrRtrim:
+						func = rtrim1;
+						break;
+					case jpiStrBtrim:
+						func = btrim1;
+						break;
+					default:;
+				}
+				resStr = TextDatumGetCString(DirectFunctionCall1Coll(func,
+																	 DEFAULT_COLLATION_OID, str));
+				break;
+			}
+
+		case jpiStrLower:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(lower, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiStrUpper:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(upper, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiStrInitcap:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(initcap, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiStrReplace:
+			{
+				char	   *from_str,
+						   *to_str;
+				int			from_len,
+							to_len;
+
+				jspGetLeftArg(jsp, &elem);
+				if (elem.type != jpiString)
+					elog(ERROR, "invalid jsonpath item type for .replace() from");
+
+				from_str = jspGetString(&elem, &from_len);
+
+				jspGetRightArg(jsp, &elem);
+				if (elem.type != jpiString)
+					elog(ERROR, "invalid jsonpath item type for .replace() to");
+
+				to_str = jspGetString(&elem, &to_len);
+
+				resStr = TextDatumGetCString(DirectFunctionCall3Coll(replace_text,
+																	 C_COLLATION_OID,
+																	 CStringGetTextDatum(tmp),
+																	 CStringGetTextDatum(from_str),
+																	 CStringGetTextDatum(to_str)));
+				break;
+			}
+		case jpiStrSplitPart:
+			{
+				char	   *from_str;
+				Numeric		n;
+				int			from_len;
+
+				jspGetLeftArg(jsp, &elem);
+				if (elem.type != jpiString)
+					elog(ERROR, "invalid jsonpath item type for .split_part()");
+
+				from_str = jspGetString(&elem, &from_len);
+
+				jspGetRightArg(jsp, &elem);
+				if (elem.type != jpiNumeric)
+					elog(ERROR, "invalid jsonpath item type for .split_part()");
+
+				n = jspGetNumeric(&elem);
+
+				resStr = TextDatumGetCString(DirectFunctionCall3Coll(split_part,
+																	 C_COLLATION_OID,
+																	 CStringGetTextDatum(tmp),
+																	 CStringGetTextDatum(from_str),
+																	 DirectFunctionCall1(numeric_int8, NumericGetDatum(n))));
+				break;
+			}
+		default:
+			elog(ERROR, "unsupported jsonpath item type: %d", jsp->type);
+	}
+
+	if (resStr)
+		res = jperOk;
+
+	hasNext = jspGetNext(jsp, &elem);
+
+	if (!hasNext && !found)
+		return res;
+
+	jb = hasNext ? &jbvbuf : palloc(sizeof(*jb));
+
+	/* Create the appropriate jb value to return */
+	switch (jsp->type)
+	{
+			/* Cases for functions that return text */
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrReplace:
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
+		case jpiStrInitcap:
+		case jpiStrSplitPart:
+			jb->type = jbvString;
+			jb->val.string.val = resStr;
+			jb->val.string.len = strlen(jb->val.string.val);
+		default:
+			;
+			/* cant' happen */
+	}
+
+	return executeNextItem(cxt, jsp, &elem, jb, found, hasNext);
+}
+
 /*
  * Implementation of .keyvalue() method.
  *
diff --git a/src/backend/utils/adt/jsonpath_gram.y b/src/backend/utils/adt/jsonpath_gram.y
index 0b16cec18c4..53bf779e152 100644
--- a/src/backend/utils/adt/jsonpath_gram.y
+++ b/src/backend/utils/adt/jsonpath_gram.y
@@ -86,6 +86,8 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 %token	<str>		DATETIME_P
 %token	<str>		BIGINT_P BOOLEAN_P DATE_P DECIMAL_P INTEGER_P NUMBER_P
 %token	<str>		STRINGFUNC_P TIME_P TIME_TZ_P TIMESTAMP_P TIMESTAMP_TZ_P
+%token	<str>		STR_REPLACE_P STR_LOWER_P STR_UPPER_P STR_LTRIM_P STR_RTRIM_P STR_BTRIM_P
+					STR_INITCAP_P STR_SPLIT_PART_P
 
 %type	<result>	result
 
@@ -95,7 +97,7 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 					str_elem opt_str_arg int_elem
 					uint_elem opt_uint_arg
 
-%type	<elems>		accessor_expr int_list opt_int_list
+%type	<elems>		accessor_expr int_list opt_int_list str_int_args str_str_args
 
 %type	<indexs>	index_list
 
@@ -278,6 +280,16 @@ accessor_op:
 		{ $$ = makeItemUnary(jpiTimestamp, $4); }
 	| '.' TIMESTAMP_TZ_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimestampTz, $4); }
+	| '.' STR_REPLACE_P '(' str_str_args ')'
+		{ $$ = makeItemBinary(jpiStrReplace, linitial($4), lsecond($4)); }
+	| '.' STR_SPLIT_PART_P '(' str_int_args ')'
+		{ $$ = makeItemBinary(jpiStrSplitPart, linitial($4), lsecond($4)); }
+	| '.' STR_LTRIM_P '(' opt_str_arg ')'
+		{ $$ = makeItemUnary(jpiStrLtrim, $4); }
+	| '.' STR_RTRIM_P '(' opt_str_arg ')'
+		{ $$ = makeItemUnary(jpiStrRtrim, $4); }
+	| '.' STR_BTRIM_P '(' opt_str_arg ')'
+		{ $$ = makeItemUnary(jpiStrBtrim, $4); }
 	;
 
 int_elem:
@@ -317,6 +329,14 @@ opt_str_arg:
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
+str_int_args:
+	str_elem ',' int_elem			{ $$ = list_make2($1, $3); }
+	;
+
+str_str_args:
+	str_elem ',' str_elem 			{ $$ = list_make2($1, $3); }
+	;
+
 key:
 	key_name						{ $$ = makeItemKey(&$1); }
 	;
@@ -357,6 +377,9 @@ key_name:
 	| TIME_TZ_P
 	| TIMESTAMP_P
 	| TIMESTAMP_TZ_P
+	| STR_LTRIM_P
+	| STR_RTRIM_P
+	| STR_BTRIM_P
 	;
 
 method:
@@ -373,6 +396,9 @@ method:
 	| INTEGER_P						{ $$ = jpiInteger; }
 	| NUMBER_P						{ $$ = jpiNumber; }
 	| STRINGFUNC_P					{ $$ = jpiStringFunc; }
+	| STR_LOWER_P					{ $$ = jpiStrLower; }
+	| STR_UPPER_P					{ $$ = jpiStrUpper; }
+	| STR_INITCAP_P					{ $$ = jpiStrInitcap; }
 	;
 %%
 
diff --git a/src/backend/utils/adt/jsonpath_scan.l b/src/backend/utils/adt/jsonpath_scan.l
index c7aab83eeb4..69c61f98500 100644
--- a/src/backend/utils/adt/jsonpath_scan.l
+++ b/src/backend/utils/adt/jsonpath_scan.l
@@ -413,8 +413,13 @@ static const JsonPathKeyword keywords[] = {
 	{4, true, TRUE_P, "true"},
 	{4, false, TYPE_P, "type"},
 	{4, false, WITH_P, "with"},
+	{5, false, STR_BTRIM_P, "btrim"},
 	{5, true, FALSE_P, "false"},
 	{5, false, FLOOR_P, "floor"},
+	{5, false, STR_LOWER_P, "lower"},
+	{5, false, STR_LTRIM_P, "ltrim"},
+	{5, false, STR_RTRIM_P, "rtrim"},
+	{5, false, STR_UPPER_P, "upper"},
 	{6, false, BIGINT_P, "bigint"},
 	{6, false, DOUBLE_P, "double"},
 	{6, false, EXISTS_P, "exists"},
@@ -425,13 +430,16 @@ static const JsonPathKeyword keywords[] = {
 	{7, false, BOOLEAN_P, "boolean"},
 	{7, false, CEILING_P, "ceiling"},
 	{7, false, DECIMAL_P, "decimal"},
+	{7, false, STR_INITCAP_P, "initcap"},
 	{7, false, INTEGER_P, "integer"},
+	{7, false, STR_REPLACE_P, "replace"},
 	{7, false, TIME_TZ_P, "time_tz"},
 	{7, false, UNKNOWN_P, "unknown"},
 	{8, false, DATETIME_P, "datetime"},
 	{8, false, KEYVALUE_P, "keyvalue"},
 	{9, false, TIMESTAMP_P, "timestamp"},
 	{10, false, LIKE_REGEX_P, "like_regex"},
+	{10,false, STR_SPLIT_PART_P, "split_part"},
 	{12, false, TIMESTAMP_TZ_P, "timestamp_tz"},
 };
 
diff --git a/src/include/utils/jsonpath.h b/src/include/utils/jsonpath.h
index 23a76d233e9..2d0c53f7b06 100644
--- a/src/include/utils/jsonpath.h
+++ b/src/include/utils/jsonpath.h
@@ -115,6 +115,14 @@ typedef enum JsonPathItemType
 	jpiTimeTz,					/* .time_tz() item method */
 	jpiTimestamp,				/* .timestamp() item method */
 	jpiTimestampTz,				/* .timestamp_tz() item method */
+	jpiStrReplace,				/* .replace() item method */
+	jpiStrLower,				/* .lower() item method */
+	jpiStrUpper,				/* .upper() item method */
+	jpiStrLtrim,				/* .ltrim() item method */
+	jpiStrRtrim,				/* .rtrim() item method */
+	jpiStrBtrim,				/* .btrim() item method */
+	jpiStrInitcap,				/* .initcap() item method */
+	jpiStrSplitPart,			/* .split_part() item method */
 } JsonPathItemType;
 
 /* XQuery regex mode flags for LIKE_REGEX predicate */
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e91a29..cea539717f9 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -2723,6 +2723,405 @@ select jsonb_path_query('"2023-08-15 12:34:56"', '$.timestamp().string()');
 (1 row)
 
 rollback;
+-- test .ltrim()
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"zzzytest"', '$.ltrim("xyz")');
+ jsonb_path_query 
+------------------
+ "test"
+(1 row)
+
+select jsonb_path_query('null', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('null', '$.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.ltrim()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('{}', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('true', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('1234', '$.ltrim().type()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim()');
+  jsonb_path_query_array  
+--------------------------
+ ["maybe  ", "yes", "no"]
+(1 row)
+
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .rtrim()
+select jsonb_path_query('"   hello   "', '$.rtrim(" ")');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+select jsonb_path_query('"testxxzx"', '$.rtrim("xyz")');
+ jsonb_path_query 
+------------------
+ "test"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+-- test .btrim()
+select jsonb_path_query('"   hello   "', '$.btrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+select jsonb_path_query('"xyxtrimyyx"', '$.btrim("xyz")');
+ jsonb_path_query 
+------------------
+ "trim"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.btrim()');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.btrim()');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+-- test .lower()
+select jsonb_path_query('null', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('null', '$.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.lower()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('{}', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.lower()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.lower()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('true', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('1234', '$.lower().type()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower()');
+ jsonb_path_query_array 
+------------------------
+ ["maybe", "yes", "no"]
+(1 row)
+
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .upper()
+select jsonb_path_query('null', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('null', '$.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.upper()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('{}', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.upper()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.upper()');
+ jsonb_path_query 
+------------------
+ "1.23AAA"
+(1 row)
+
+select jsonb_path_query('1234', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('true', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('1234', '$.upper().type()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper()');
+ jsonb_path_query_array 
+------------------------
+ ["MAYBE", "YES", "NO"]
+(1 row)
+
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .initcap()
+select jsonb_path_query('null', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('null', '$.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.initcap()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('{}', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('true', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('1234', '$.initcap().type()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('["maybe yes", "probably no"]', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "Maybe Yes"
+ "Probably No"
+(2 rows)
+
+-- Test .replace()
+select jsonb_path_query('null', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('null', '$.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('["x", "y", "z"]', '$.replace("x", "bye")');
+ jsonb_path_query 
+------------------
+ "bye"
+ "y"
+ "z"
+(3 rows)
+
+select jsonb_path_query('{}', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('"hello world"', '$.replace("hello","bye")');
+ jsonb_path_query 
+------------------
+ "bye world"
+(1 row)
+
+select jsonb_path_query('"hello world"', '$.replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
+-- Test .split_part()
+select jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)');
+ jsonb_path_query 
+------------------
+ "def"
+(1 row)
+
+select jsonb_path_query('"abc,def,ghi,jkl"', '$.split_part(",", -2)');
+ jsonb_path_query 
+------------------
+ "ghi"
+(1 row)
+
+-- Test string methods play nicely together
+select jsonb_path_query('"hello world"', '$.replace("hello","bye").upper()');
+ jsonb_path_query 
+------------------
+ "BYE WORLD"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye")');
+ jsonb_path_query 
+------------------
+ "bye world"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.upper().lower().upper().replace("HELLO", "BYE")');
+ jsonb_path_query 
+------------------
+ "BYE WORLD"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
+select jsonb_path_query('"   hElLo WorlD "', '$.btrim().lower().upper().lower().replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
 -- Test .time()
 select jsonb_path_query('null', '$.time()');
 ERROR:  jsonpath item method .time() can only be applied to a string
diff --git a/src/test/regress/expected/jsonpath.out b/src/test/regress/expected/jsonpath.out
index fd9bd755f52..a13022feabd 100644
--- a/src/test/regress/expected/jsonpath.out
+++ b/src/test/regress/expected/jsonpath.out
@@ -435,6 +435,143 @@ select '$.string()'::jsonpath;
  $.string()
 (1 row)
 
+select '$.replace("hello","bye")'::jsonpath;
+         jsonpath         
+--------------------------
+ $.replace("hello","bye")
+(1 row)
+
+select '$.lower()'::jsonpath;
+ jsonpath  
+-----------
+ $.lower()
+(1 row)
+
+select '$.upper()'::jsonpath;
+ jsonpath  
+-----------
+ $.upper()
+(1 row)
+
+select '$.lower().upper().lower().replace("hello","bye")'::jsonpath;
+                     jsonpath                     
+--------------------------------------------------
+ $.lower().upper().lower().replace("hello","bye")
+(1 row)
+
+select '$.ltrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.ltrim()
+(1 row)
+
+select '$.ltrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.ltrim("xyz")
+(1 row)
+
+select '$.rtrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.rtrim()
+(1 row)
+
+select '$.rtrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.rtrim("xyz")
+(1 row)
+
+select '$.btrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.btrim()
+(1 row)
+
+select '$.btrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.btrim("xyz")
+(1 row)
+
+select '$.initcap()'::jsonpath;
+  jsonpath   
+-------------
+ $.initcap()
+(1 row)
+
+select '$.split_part("~@~", 2)'::jsonpath;
+       jsonpath        
+-----------------------
+ $.split_part("~@~",2)
+(1 row)
+
+-- Parse errors
+select '$.replace("hello")'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.replace("hello")'::jsonpath;
+               ^
+select '$.replace()'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.replace()'::jsonpath;
+               ^
+select '$.replace("hello","bye","extra")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.replace("hello","bye","extra")'::jsonpath;
+               ^
+select '$.split_part("~@~")'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.split_part("~@~")'::jsonpath;
+               ^
+select '$.split_part()'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.split_part()'::jsonpath;
+               ^
+select '$.split_part("~@~", "hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.split_part("~@~", "hi")'::jsonpath;
+               ^
+select '$.split_part("~@~", 2, "extra")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.split_part("~@~", 2, "extra")'::jsonpath;
+               ^
+select '$.lower("hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.lower("hi")'::jsonpath;
+               ^
+select '$.upper("hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.upper("hi")'::jsonpath;
+               ^
+select '$.initcap("hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.initcap("hi")'::jsonpath;
+               ^
+select '$.ltrim(42)'::jsonpath;
+ERROR:  syntax error at or near "42" of jsonpath input
+LINE 1: select '$.ltrim(42)'::jsonpath;
+               ^
+select '$.ltrim("x", "y")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.ltrim("x", "y")'::jsonpath;
+               ^
+select '$.rtrim(42)'::jsonpath;
+ERROR:  syntax error at or near "42" of jsonpath input
+LINE 1: select '$.rtrim(42)'::jsonpath;
+               ^
+select '$.rtrim("x", "y")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.rtrim("x", "y")'::jsonpath;
+               ^
+select '$.trim(42)'::jsonpath;
+ERROR:  syntax error at or near "(" of jsonpath input
+LINE 1: select '$.trim(42)'::jsonpath;
+               ^
+select '$.trim("x", "y")'::jsonpath;
+ERROR:  syntax error at or near "(" of jsonpath input
+LINE 1: select '$.trim("x", "y")'::jsonpath;
+               ^
 select '$.time()'::jsonpath;
  jsonpath 
 ----------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a5269..8169719343e 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -623,6 +623,115 @@ select jsonb_path_query('"2023-08-15 12:34:56 +5:30"', '$.timestamp_tz().string(
 select jsonb_path_query('"2023-08-15 12:34:56"', '$.timestamp().string()');
 rollback;
 
+-- test .ltrim()
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+select jsonb_path_query('"   hello   "', '$.ltrim()');
+select jsonb_path_query('"zzzytest"', '$.ltrim("xyz")');
+select jsonb_path_query('null', '$.ltrim()');
+select jsonb_path_query('null', '$.ltrim()', silent => true);
+select jsonb_path_query('[]', '$.ltrim()');
+select jsonb_path_query('[]', 'strict $.ltrim()');
+select jsonb_path_query('{}', '$.ltrim()');
+select jsonb_path_query('[]', 'strict $.ltrim()', silent => true);
+select jsonb_path_query('{}', '$.ltrim()', silent => true);
+select jsonb_path_query('1.23', '$.ltrim()');
+select jsonb_path_query('"1.23"', '$.ltrim()');
+select jsonb_path_query('"1.23aaa"', '$.ltrim()');
+select jsonb_path_query('1234', '$.ltrim()');
+select jsonb_path_query('true', '$.ltrim()');
+select jsonb_path_query('1234', '$.ltrim().type()');
+select jsonb_path_query('[2, true]', '$.ltrim()');
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim()');
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim().type()');
+
+-- test .rtrim()
+select jsonb_path_query('"   hello   "', '$.rtrim(" ")');
+select jsonb_path_query('"testxxzx"', '$.rtrim("xyz")');
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+
+-- test .btrim()
+select jsonb_path_query('"   hello   "', '$.btrim(" ")');
+select jsonb_path_query('"xyxtrimyyx"', '$.btrim("xyz")');
+select jsonb_path_query('"   hello   "', '$.btrim()');
+select jsonb_path_query('"   hello   "', '$.btrim()');
+
+-- test .lower()
+select jsonb_path_query('null', '$.lower()');
+select jsonb_path_query('null', '$.lower()', silent => true);
+select jsonb_path_query('[]', '$.lower()');
+select jsonb_path_query('[]', 'strict $.lower()');
+select jsonb_path_query('{}', '$.lower()');
+select jsonb_path_query('[]', 'strict $.lower()', silent => true);
+select jsonb_path_query('{}', '$.lower()', silent => true);
+select jsonb_path_query('1.23', '$.lower()');
+select jsonb_path_query('"1.23"', '$.lower()');
+select jsonb_path_query('"1.23aaa"', '$.lower()');
+select jsonb_path_query('1234', '$.lower()');
+select jsonb_path_query('true', '$.lower()');
+select jsonb_path_query('1234', '$.lower().type()');
+select jsonb_path_query('[2, true]', '$.lower()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower().type()');
+
+-- test .upper()
+select jsonb_path_query('null', '$.upper()');
+select jsonb_path_query('null', '$.upper()', silent => true);
+select jsonb_path_query('[]', '$.upper()');
+select jsonb_path_query('[]', 'strict $.upper()');
+select jsonb_path_query('{}', '$.upper()');
+select jsonb_path_query('[]', 'strict $.upper()', silent => true);
+select jsonb_path_query('{}', '$.upper()', silent => true);
+select jsonb_path_query('1.23', '$.upper()');
+select jsonb_path_query('"1.23"', '$.upper()');
+select jsonb_path_query('"1.23aaa"', '$.upper()');
+select jsonb_path_query('1234', '$.upper()');
+select jsonb_path_query('true', '$.upper()');
+select jsonb_path_query('1234', '$.upper().type()');
+select jsonb_path_query('[2, true]', '$.upper()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper().type()');
+
+-- test .initcap()
+select jsonb_path_query('null', '$.initcap()');
+select jsonb_path_query('null', '$.initcap()', silent => true);
+select jsonb_path_query('[]', '$.initcap()');
+select jsonb_path_query('[]', 'strict $.initcap()');
+select jsonb_path_query('{}', '$.initcap()');
+select jsonb_path_query('[]', 'strict $.initcap()', silent => true);
+select jsonb_path_query('{}', '$.initcap()', silent => true);
+select jsonb_path_query('1.23', '$.initcap()');
+select jsonb_path_query('"1.23"', '$.initcap()');
+select jsonb_path_query('"1.23aaa"', '$.initcap()');
+select jsonb_path_query('1234', '$.initcap()');
+select jsonb_path_query('true', '$.initcap()');
+select jsonb_path_query('1234', '$.initcap().type()');
+select jsonb_path_query('[2, true]', '$.initcap()');
+select jsonb_path_query('["maybe yes", "probably no"]', '$.initcap()');
+
+-- Test .replace()
+select jsonb_path_query('null', '$.replace("x", "bye")');
+select jsonb_path_query('null', '$.replace("x", "bye")', silent => true);
+select jsonb_path_query('["x", "y", "z"]', '$.replace("x", "bye")');
+select jsonb_path_query('{}', '$.replace("x", "bye")');
+select jsonb_path_query('[]', 'strict $.replace("x", "bye")', silent => true);
+select jsonb_path_query('{}', '$.replace("x", "bye")', silent => true);
+select jsonb_path_query('1.23', '$.replace("x", "bye")');
+select jsonb_path_query('"hello world"', '$.replace("hello","bye")');
+select jsonb_path_query('"hello world"', '$.replace("hello","bye") starts with "bye"');
+
+-- Test .split_part()
+select jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)');
+select jsonb_path_query('"abc,def,ghi,jkl"', '$.split_part(",", -2)');
+
+-- Test string methods play nicely together
+select jsonb_path_query('"hello world"', '$.replace("hello","bye").upper()');
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye")');
+select jsonb_path_query('"hElLo WorlD"', '$.upper().lower().upper().replace("HELLO", "BYE")');
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye") starts with "bye"');
+select jsonb_path_query('"   hElLo WorlD "', '$.btrim().lower().upper().lower().replace("hello","bye") starts with "bye"');
+
 -- Test .time()
 select jsonb_path_query('null', '$.time()');
 select jsonb_path_query('true', '$.time()');
diff --git a/src/test/regress/sql/jsonpath.sql b/src/test/regress/sql/jsonpath.sql
index 61a5270d4e8..7dd2e57e7a6 100644
--- a/src/test/regress/sql/jsonpath.sql
+++ b/src/test/regress/sql/jsonpath.sql
@@ -78,6 +78,37 @@ select '$.boolean()'::jsonpath;
 select '$.date()'::jsonpath;
 select '$.decimal(4,2)'::jsonpath;
 select '$.string()'::jsonpath;
+select '$.replace("hello","bye")'::jsonpath;
+select '$.lower()'::jsonpath;
+select '$.upper()'::jsonpath;
+select '$.lower().upper().lower().replace("hello","bye")'::jsonpath;
+select '$.ltrim()'::jsonpath;
+select '$.ltrim("xyz")'::jsonpath;
+select '$.rtrim()'::jsonpath;
+select '$.rtrim("xyz")'::jsonpath;
+select '$.btrim()'::jsonpath;
+select '$.btrim("xyz")'::jsonpath;
+select '$.initcap()'::jsonpath;
+select '$.split_part("~@~", 2)'::jsonpath;
+
+-- Parse errors
+select '$.replace("hello")'::jsonpath;
+select '$.replace()'::jsonpath;
+select '$.replace("hello","bye","extra")'::jsonpath;
+select '$.split_part("~@~")'::jsonpath;
+select '$.split_part()'::jsonpath;
+select '$.split_part("~@~", "hi")'::jsonpath;
+select '$.split_part("~@~", 2, "extra")'::jsonpath;
+select '$.lower("hi")'::jsonpath;
+select '$.upper("hi")'::jsonpath;
+select '$.initcap("hi")'::jsonpath;
+select '$.ltrim(42)'::jsonpath;
+select '$.ltrim("x", "y")'::jsonpath;
+select '$.rtrim(42)'::jsonpath;
+select '$.rtrim("x", "y")'::jsonpath;
+select '$.trim(42)'::jsonpath;
+select '$.trim("x", "y")'::jsonpath;
+
 select '$.time()'::jsonpath;
 select '$.time(6)'::jsonpath;
 select '$.time_tz()'::jsonpath;
-- 
2.49.0

From b63773f20c615a79b84522cfcb1b68d4bdfdc7a9 Mon Sep 17 00:00:00 2001
From: "David E. Wheeler" <david@justatheory.com>
Date: Mon, 2 Jun 2025 17:14:10 -0400
Subject: [PATCH v10 1/2] Rename jsonpath method arg tokens

Rename the `csv_` tokens to `int_`, because they represent signed or
unsigned integers, as follows:

*   `csv_elem` => `int_elem`
*   `csv_list` => `int_list`
*   `opt_csv_list` => `opt_int_list`

Rename the `datetime_precision` tokens to `uint_arg`, as they represent
unsigned integers and will be useful for other methods in the future, as
follows:

*   `datetime_precision` => `uint_elem`
*   `opt_datetime_precision` => `opt_uint_arg`

Rename the `datetime_template` tokens to `str_arg`, as they represent
strings and will be useful for other methods in the future, as follows:

*   `datetime_template` => `str_elem`
*   `opt_datetime_template` => `opt_str_arg`
---
 src/backend/utils/adt/jsonpath_gram.y | 42 +++++++++++++--------------
 1 file changed, 21 insertions(+), 21 deletions(-)

diff --git a/src/backend/utils/adt/jsonpath_gram.y b/src/backend/utils/adt/jsonpath_gram.y
index 499745a8fef..0b16cec18c4 100644
--- a/src/backend/utils/adt/jsonpath_gram.y
+++ b/src/backend/utils/adt/jsonpath_gram.y
@@ -92,10 +92,10 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 %type	<value>		scalar_value path_primary expr array_accessor
 					any_path accessor_op key predicate delimited_predicate
 					index_elem starts_with_initial expr_or_predicate
-					datetime_template opt_datetime_template csv_elem
-					datetime_precision opt_datetime_precision
+					str_elem opt_str_arg int_elem
+					uint_elem opt_uint_arg
 
-%type	<elems>		accessor_expr csv_list opt_csv_list
+%type	<elems>		accessor_expr int_list opt_int_list
 
 %type	<indexs>	index_list
 
@@ -254,7 +254,7 @@ accessor_op:
 	| '.' any_path					{ $$ = $2; }
 	| '.' method '(' ')'			{ $$ = makeItemType($2); }
 	| '?' '(' predicate ')'			{ $$ = makeItemUnary(jpiFilter, $3); }
-	| '.' DECIMAL_P '(' opt_csv_list ')'
+	| '.' DECIMAL_P '(' opt_int_list ')'
 		{
 			if (list_length($4) == 0)
 				$$ = makeItemBinary(jpiDecimal, NULL, NULL);
@@ -268,19 +268,19 @@ accessor_op:
 						 errmsg("invalid input syntax for type %s", "jsonpath"),
 						 errdetail(".decimal() can only have an optional precision[,scale].")));
 		}
-	| '.' DATETIME_P '(' opt_datetime_template ')'
+	| '.' DATETIME_P '(' opt_str_arg ')'
 		{ $$ = makeItemUnary(jpiDatetime, $4); }
-	| '.' TIME_P '(' opt_datetime_precision ')'
+	| '.' TIME_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTime, $4); }
-	| '.' TIME_TZ_P '(' opt_datetime_precision ')'
+	| '.' TIME_TZ_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimeTz, $4); }
-	| '.' TIMESTAMP_P '(' opt_datetime_precision ')'
+	| '.' TIMESTAMP_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimestamp, $4); }
-	| '.' TIMESTAMP_TZ_P '(' opt_datetime_precision ')'
+	| '.' TIMESTAMP_TZ_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimestampTz, $4); }
 	;
 
-csv_elem:
+int_elem:
 	INT_P
 		{ $$ = makeItemNumeric(&$1); }
 	| '+' INT_P %prec UMINUS
@@ -289,31 +289,31 @@ csv_elem:
 		{ $$ = makeItemUnary(jpiMinus, makeItemNumeric(&$2)); }
 	;
 
-csv_list:
-	csv_elem						{ $$ = list_make1($1); }
-	| csv_list ',' csv_elem			{ $$ = lappend($1, $3); }
+int_list:
+	int_elem						{ $$ = list_make1($1); }
+	| int_list ',' int_elem			{ $$ = lappend($1, $3); }
 	;
 
-opt_csv_list:
-	csv_list						{ $$ = $1; }
+opt_int_list:
+	int_list						{ $$ = $1; }
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
-datetime_precision:
+uint_elem:
 	INT_P							{ $$ = makeItemNumeric(&$1); }
 	;
 
-opt_datetime_precision:
-	datetime_precision				{ $$ = $1; }
+opt_uint_arg:
+	uint_elem						{ $$ = $1; }
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
-datetime_template:
+str_elem:
 	STRING_P						{ $$ = makeItemString(&$1); }
 	;
 
-opt_datetime_template:
-	datetime_template				{ $$ = $1; }
+opt_str_arg:
+	str_elem						{ $$ = $1; }
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
-- 
2.49.0

From 98f8bcdcda4296936e9f090ce6f2e15c6b216167 Mon Sep 17 00:00:00 2001
From: Florents Tselai <florents.tselai@gmail.com>
Date: Thu, 10 Jul 2025 18:38:09 -0400
Subject: [PATCH v10 2/2] Add additional jsonpath string methods

Add the following jsonpath methods:

*   l/r/btrim()
*   lower(), upper()
*   initcap()
*   replace()
*   split_part()

Each simply dispatches to the standard string processing functions.
These depend on the locale, but since it's set at `initdb`, they can be
considered immutable and therefore allowed in any jsonpath expression.
---
 doc/src/sgml/func.sgml                       | 140 +++++++
 src/backend/utils/adt/jsonpath.c             | 117 +++++-
 src/backend/utils/adt/jsonpath_exec.c        | 206 ++++++++++
 src/backend/utils/adt/jsonpath_gram.y        |  28 +-
 src/backend/utils/adt/jsonpath_scan.l        |   8 +
 src/include/utils/jsonpath.h                 |   8 +
 src/test/regress/expected/jsonb_jsonpath.out | 399 +++++++++++++++++++
 src/test/regress/expected/jsonpath.out       | 137 +++++++
 src/test/regress/sql/jsonb_jsonpath.sql      | 109 +++++
 src/test/regress/sql/jsonpath.sql            |  31 ++
 10 files changed, 1178 insertions(+), 5 deletions(-)

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index c28aa71f570..23710921869 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -18637,6 +18637,146 @@ ERROR:  jsonpath member accessor can only be applied to an object
         <returnvalue>[{"id": 0, "key": "x", "value": "20"}, {"id": 0, "key": "y", "value": 32}]</returnvalue>
        </para></entry>
       </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>lower()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String converted to all lower case according to the rules of the database's locale.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"TOM"', '$.lower()')</literal>
+        <returnvalue>"tom"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>upper()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String converted to all upper case according to the rules of the database's locale.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"tom"', '$.upper()')</literal>
+        <returnvalue>"TOM"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>initcap()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the first letter of each word converted to upper case
+        according to the rules of the database's locale. Words are sequences
+        of alphanumeric characters separated by non-alphanumeric characters.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"hi THOMAS"', '$.initcap()')</literal>
+        <returnvalue>"Hi Thomas"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>replace(<replaceable>from</replaceable>, <replaceable>to</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with all occurrences of substring from replaced with substring to.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"abcdefabcdef"', '$.replace("cd", "XX")')</literal>
+        <returnvalue>"abXXefabXXef"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>split_part(<replaceable>delimiter</replaceable>, <replaceable>n</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String split at occurrences of <replaceable>delimiter</replaceable>
+        and returns the <replaceable>n</replaceable>'th field (counting from
+        one) or, when <replaceable>n</replaceable> is negative, returns the
+        |<replaceable>n</replaceable>|'th-from-last field.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)')</literal>
+        <returnvalue>"def"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"abc,def,ghi,jkl"', '$.split_part(",", 2)')</literal>
+        <returnvalue>"ghi"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>ltrim(<replaceable>characters</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the longest string containing only spaces or the
+        characters in <replaceable>characters</replaceable> removed from the
+        start of <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal> jsonb_path_query('"  hello"', '$.ltrim()')</literal>
+        <returnvalue>"hello"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"zzzytest"', '$.ltrim("xyz")')</literal>
+        <returnvalue>"test"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>rtrim([ <replaceable>characters</replaceable> ])</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the longest string containing only spaces or the
+        characters in <replaceable>characters</replaceable> removed from the
+        end of <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"hello  "', '$.rtrim()')</literal>
+        <returnvalue>"hello"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"testxxzx"', '$.rtrim("xyz")')</literal>
+        <returnvalue>"test"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>btrim([ <replaceable>characters</replaceable> ])</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the longest string containing only spaces or the
+        characters in <replaceable>characters</replaceable> removed from the
+        start and end of <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"  hello  "', '$.btrim()')</literal>
+        <returnvalue>"hello"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"xyxtrimyyx"', '$.btrim("xyz")')</literal>
+        <returnvalue>"trim"</returnvalue>
+       </para></entry>
+      </row>
+
      </tbody>
     </tgroup>
    </table>
diff --git a/src/backend/utils/adt/jsonpath.c b/src/backend/utils/adt/jsonpath.c
index 762f7e8a09d..f3f2119a4a8 100644
--- a/src/backend/utils/adt/jsonpath.c
+++ b/src/backend/utils/adt/jsonpath.c
@@ -298,6 +298,8 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 		case jpiMod:
 		case jpiStartsWith:
 		case jpiDecimal:
+		case jpiStrReplace:
+		case jpiStrSplitPart:
 			{
 				/*
 				 * First, reserve place for left/right arg's positions, then
@@ -362,6 +364,9 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 		case jpiTimeTz:
 		case jpiTimestamp:
 		case jpiTimestampTz:
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
 			{
 				int32		arg = reserveSpaceForItemPointer(buf);
 
@@ -457,6 +462,9 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 		case jpiInteger:
 		case jpiNumber:
 		case jpiStringFunc:
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrInitcap:
 			break;
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", item->type);
@@ -831,6 +839,60 @@ printJsonPathItem(StringInfo buf, JsonPathItem *v, bool inKey,
 			}
 			appendStringInfoChar(buf, ')');
 			break;
+		case jpiStrReplace:
+			appendStringInfoString(buf, ".replace(");
+			jspGetLeftArg(v, &elem);
+			printJsonPathItem(buf, &elem, false, false);
+			appendStringInfoChar(buf, ',');
+			jspGetRightArg(v, &elem);
+			printJsonPathItem(buf, &elem, false, false);
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrSplitPart:
+			appendStringInfoString(buf, ".split_part(");
+			jspGetLeftArg(v, &elem);
+			printJsonPathItem(buf, &elem, false, false);
+			appendStringInfoChar(buf, ',');
+			jspGetRightArg(v, &elem);
+			printJsonPathItem(buf, &elem, false, false);
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrLower:
+			appendStringInfoString(buf, ".lower()");
+			break;
+		case jpiStrUpper:
+			appendStringInfoString(buf, ".upper()");
+			break;
+		case jpiStrInitcap:
+			appendStringInfoString(buf, ".initcap()");
+			break;
+		case jpiStrLtrim:
+			appendStringInfoString(buf, ".ltrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrRtrim:
+			appendStringInfoString(buf, ".rtrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrBtrim:
+			appendStringInfoString(buf, ".btrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", v->type);
 	}
@@ -906,6 +968,12 @@ jspOperationName(JsonPathItemType type)
 			return "number";
 		case jpiStringFunc:
 			return "string";
+		case jpiStrReplace:
+			return "replace";
+		case jpiStrLower:
+			return "lower";
+		case jpiStrUpper:
+			return "upper";
 		case jpiTime:
 			return "time";
 		case jpiTimeTz:
@@ -914,6 +982,16 @@ jspOperationName(JsonPathItemType type)
 			return "timestamp";
 		case jpiTimestampTz:
 			return "timestamp_tz";
+		case jpiStrLtrim:
+			return "ltrim";
+		case jpiStrRtrim:
+			return "rtrim";
+		case jpiStrBtrim:
+			return "btrim";
+		case jpiStrInitcap:
+			return "initcap";
+		case jpiStrSplitPart:
+			return "split_part";
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", type);
 			return NULL;
@@ -1016,6 +1094,9 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 		case jpiInteger:
 		case jpiNumber:
 		case jpiStringFunc:
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrInitcap:
 			break;
 		case jpiString:
 		case jpiKey:
@@ -1041,6 +1122,8 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 		case jpiMod:
 		case jpiStartsWith:
 		case jpiDecimal:
+		case jpiStrReplace:
+		case jpiStrSplitPart:
 			read_int32(v->content.args.left, base, pos);
 			read_int32(v->content.args.right, base, pos);
 			break;
@@ -1055,6 +1138,9 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 		case jpiTimeTz:
 		case jpiTimestamp:
 		case jpiTimestampTz:
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
 			read_int32(v->content.arg, base, pos);
 			break;
 		case jpiIndexArray:
@@ -1090,7 +1176,10 @@ jspGetArg(JsonPathItem *v, JsonPathItem *a)
 		   v->type == jpiTime ||
 		   v->type == jpiTimeTz ||
 		   v->type == jpiTimestamp ||
-		   v->type == jpiTimestampTz);
+		   v->type == jpiTimestampTz ||
+		   v->type == jpiStrLtrim ||
+		   v->type == jpiStrRtrim ||
+		   v->type == jpiStrBtrim);
 
 	jspInitByBuffer(a, v->base, v->content.arg);
 }
@@ -1149,10 +1238,18 @@ jspGetNext(JsonPathItem *v, JsonPathItem *a)
 			   v->type == jpiInteger ||
 			   v->type == jpiNumber ||
 			   v->type == jpiStringFunc ||
+			   v->type == jpiStrReplace ||
+			   v->type == jpiStrLower ||
+			   v->type == jpiStrUpper ||
 			   v->type == jpiTime ||
 			   v->type == jpiTimeTz ||
 			   v->type == jpiTimestamp ||
-			   v->type == jpiTimestampTz);
+			   v->type == jpiTimestampTz ||
+			   v->type == jpiStrLtrim ||
+			   v->type == jpiStrRtrim ||
+			   v->type == jpiStrBtrim ||
+			   v->type == jpiStrInitcap ||
+			   v->type == jpiStrSplitPart);
 
 		if (a)
 			jspInitByBuffer(a, v->base, v->nextPos);
@@ -1179,7 +1276,9 @@ jspGetLeftArg(JsonPathItem *v, JsonPathItem *a)
 		   v->type == jpiDiv ||
 		   v->type == jpiMod ||
 		   v->type == jpiStartsWith ||
-		   v->type == jpiDecimal);
+		   v->type == jpiDecimal ||
+		   v->type == jpiStrReplace ||
+		   v->type == jpiStrSplitPart);
 
 	jspInitByBuffer(a, v->base, v->content.args.left);
 }
@@ -1201,7 +1300,9 @@ jspGetRightArg(JsonPathItem *v, JsonPathItem *a)
 		   v->type == jpiDiv ||
 		   v->type == jpiMod ||
 		   v->type == jpiStartsWith ||
-		   v->type == jpiDecimal);
+		   v->type == jpiDecimal ||
+		   v->type == jpiStrReplace ||
+		   v->type == jpiStrSplitPart);
 
 	jspInitByBuffer(a, v->base, v->content.args.right);
 }
@@ -1501,6 +1602,14 @@ jspIsMutableWalker(JsonPathItem *jpi, struct JsonPathMutableContext *cxt)
 			case jpiInteger:
 			case jpiNumber:
 			case jpiStringFunc:
+			case jpiStrReplace:
+			case jpiStrLower:
+			case jpiStrUpper:
+			case jpiStrLtrim:
+			case jpiStrRtrim:
+			case jpiStrBtrim:
+			case jpiStrInitcap:
+			case jpiStrSplitPart:
 				status = jpdsNonDateTime;
 				break;
 
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index dbab24737ef..28a04b24bfa 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -301,6 +301,8 @@ static JsonPathExecResult executeNumericItemMethod(JsonPathExecContext *cxt,
 												   JsonValueList *found);
 static JsonPathExecResult executeDateTimeMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
 												JsonbValue *jb, JsonValueList *found);
+static JsonPathExecResult executeStringInternalMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
+													  JsonbValue *jb, JsonValueList *found);
 static JsonPathExecResult executeKeyValueMethod(JsonPathExecContext *cxt,
 												JsonPathItem *jsp, JsonbValue *jb, JsonValueList *found);
 static JsonPathExecResult appendBoolResult(JsonPathExecContext *cxt,
@@ -1659,6 +1661,23 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
 			}
 			break;
 
+		case jpiStrLtrim:
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrReplace:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
+		case jpiStrInitcap:
+		case jpiStrSplitPart:
+			{
+				if (unwrap && JsonbType(jb) == jbvArray)
+					return executeItemUnwrapTargetArray(cxt, jsp, jb, found, false);
+
+				return executeStringInternalMethod(cxt, jsp, jb, found);
+			}
+			break;
+
+
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", jsp->type);
 	}
@@ -2792,6 +2811,193 @@ executeDateTimeMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
 	return executeNextItem(cxt, jsp, &elem, jb, found, hasNext);
 }
 
+/*
+ * Implementation of .upper(), lower() et. al. methods,
+ * that forward their actual implementation to internal functions.
+ */
+static JsonPathExecResult
+executeStringInternalMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
+							JsonbValue *jb, JsonValueList *found)
+{
+	Assert(jsp->type == jpiStrLower ||
+		   jsp->type == jpiStrUpper ||
+		   jsp->type == jpiStrReplace ||
+		   jsp->type == jpiStrLtrim ||
+		   jsp->type == jpiStrRtrim ||
+		   jsp->type == jpiStrBtrim ||
+		   jsp->type == jpiStrInitcap ||
+		   jsp->type == jpiStrSplitPart);
+	JsonbValue	jbvbuf;
+	bool		hasNext;
+	JsonPathExecResult res = jperNotFound;
+	JsonPathItem elem;
+	Datum		str;			/* Datum representation for the current string
+								 * value. The first argument to internal
+								 * functions */
+	char	   *tmp = NULL;
+	char	   *resStr = NULL;
+
+	if (!(jb = getScalar(jb, jbvString)))
+		RETURN_ERROR(ereport(ERROR,
+							 (errcode(ERRCODE_INVALID_ARGUMENT_FOR_SQL_JSON_DATETIME_FUNCTION),
+							  errmsg("jsonpath item method .%s() can only be applied to a string",
+									 jspOperationName(jsp->type)))));
+
+	tmp = pnstrdup(jb->val.string.val, jb->val.string.len);
+	str = CStringGetTextDatum(tmp);
+
+	/* Internal string functions that accept no arguments */
+	switch (jsp->type)
+	{
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
+			{
+				char	   *characters_str;
+				int			characters_len;
+				PGFunction	func = NULL;
+
+				if (jsp->content.arg)
+				{
+					switch (jsp->type)
+					{
+						case jpiStrLtrim:
+							func = ltrim;
+							break;
+						case jpiStrRtrim:
+							func = rtrim;
+							break;
+						case jpiStrBtrim:
+							func = btrim;
+							break;
+						default:;
+					}
+					jspGetArg(jsp, &elem);
+					if (elem.type != jpiString)
+						elog(ERROR, "invalid jsonpath item type for .%s() argument", jspOperationName(jsp->type));
+
+					characters_str = jspGetString(&elem, &characters_len);
+					resStr = TextDatumGetCString(DirectFunctionCall2Coll(func,
+																		 DEFAULT_COLLATION_OID, str,
+																		 CStringGetTextDatum(characters_str)));
+					break;
+				}
+
+				switch (jsp->type)
+				{
+					case jpiStrLtrim:
+						func = ltrim1;
+						break;
+					case jpiStrRtrim:
+						func = rtrim1;
+						break;
+					case jpiStrBtrim:
+						func = btrim1;
+						break;
+					default:;
+				}
+				resStr = TextDatumGetCString(DirectFunctionCall1Coll(func,
+																	 DEFAULT_COLLATION_OID, str));
+				break;
+			}
+
+		case jpiStrLower:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(lower, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiStrUpper:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(upper, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiStrInitcap:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(initcap, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiStrReplace:
+			{
+				char	   *from_str,
+						   *to_str;
+				int			from_len,
+							to_len;
+
+				jspGetLeftArg(jsp, &elem);
+				if (elem.type != jpiString)
+					elog(ERROR, "invalid jsonpath item type for .replace() from");
+
+				from_str = jspGetString(&elem, &from_len);
+
+				jspGetRightArg(jsp, &elem);
+				if (elem.type != jpiString)
+					elog(ERROR, "invalid jsonpath item type for .replace() to");
+
+				to_str = jspGetString(&elem, &to_len);
+
+				resStr = TextDatumGetCString(DirectFunctionCall3Coll(replace_text,
+																	 C_COLLATION_OID,
+																	 CStringGetTextDatum(tmp),
+																	 CStringGetTextDatum(from_str),
+																	 CStringGetTextDatum(to_str)));
+				break;
+			}
+		case jpiStrSplitPart:
+			{
+				char	   *from_str;
+				Numeric		n;
+				int			from_len;
+
+				jspGetLeftArg(jsp, &elem);
+				if (elem.type != jpiString)
+					elog(ERROR, "invalid jsonpath item type for .split_part()");
+
+				from_str = jspGetString(&elem, &from_len);
+
+				jspGetRightArg(jsp, &elem);
+				if (elem.type != jpiNumeric)
+					elog(ERROR, "invalid jsonpath item type for .split_part()");
+
+				n = jspGetNumeric(&elem);
+
+				resStr = TextDatumGetCString(DirectFunctionCall3Coll(split_part,
+																	 C_COLLATION_OID,
+																	 CStringGetTextDatum(tmp),
+																	 CStringGetTextDatum(from_str),
+																	 DirectFunctionCall1(numeric_int8, NumericGetDatum(n))));
+				break;
+			}
+		default:
+			elog(ERROR, "unsupported jsonpath item type: %d", jsp->type);
+	}
+
+	if (resStr)
+		res = jperOk;
+
+	hasNext = jspGetNext(jsp, &elem);
+
+	if (!hasNext && !found)
+		return res;
+
+	jb = hasNext ? &jbvbuf : palloc(sizeof(*jb));
+
+	/* Create the appropriate jb value to return */
+	switch (jsp->type)
+	{
+			/* Cases for functions that return text */
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrReplace:
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
+		case jpiStrInitcap:
+		case jpiStrSplitPart:
+			jb->type = jbvString;
+			jb->val.string.val = resStr;
+			jb->val.string.len = strlen(jb->val.string.val);
+		default:
+			;
+			/* cant' happen */
+	}
+
+	return executeNextItem(cxt, jsp, &elem, jb, found, hasNext);
+}
+
 /*
  * Implementation of .keyvalue() method.
  *
diff --git a/src/backend/utils/adt/jsonpath_gram.y b/src/backend/utils/adt/jsonpath_gram.y
index 0b16cec18c4..53bf779e152 100644
--- a/src/backend/utils/adt/jsonpath_gram.y
+++ b/src/backend/utils/adt/jsonpath_gram.y
@@ -86,6 +86,8 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 %token	<str>		DATETIME_P
 %token	<str>		BIGINT_P BOOLEAN_P DATE_P DECIMAL_P INTEGER_P NUMBER_P
 %token	<str>		STRINGFUNC_P TIME_P TIME_TZ_P TIMESTAMP_P TIMESTAMP_TZ_P
+%token	<str>		STR_REPLACE_P STR_LOWER_P STR_UPPER_P STR_LTRIM_P STR_RTRIM_P STR_BTRIM_P
+					STR_INITCAP_P STR_SPLIT_PART_P
 
 %type	<result>	result
 
@@ -95,7 +97,7 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 					str_elem opt_str_arg int_elem
 					uint_elem opt_uint_arg
 
-%type	<elems>		accessor_expr int_list opt_int_list
+%type	<elems>		accessor_expr int_list opt_int_list str_int_args str_str_args
 
 %type	<indexs>	index_list
 
@@ -278,6 +280,16 @@ accessor_op:
 		{ $$ = makeItemUnary(jpiTimestamp, $4); }
 	| '.' TIMESTAMP_TZ_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimestampTz, $4); }
+	| '.' STR_REPLACE_P '(' str_str_args ')'
+		{ $$ = makeItemBinary(jpiStrReplace, linitial($4), lsecond($4)); }
+	| '.' STR_SPLIT_PART_P '(' str_int_args ')'
+		{ $$ = makeItemBinary(jpiStrSplitPart, linitial($4), lsecond($4)); }
+	| '.' STR_LTRIM_P '(' opt_str_arg ')'
+		{ $$ = makeItemUnary(jpiStrLtrim, $4); }
+	| '.' STR_RTRIM_P '(' opt_str_arg ')'
+		{ $$ = makeItemUnary(jpiStrRtrim, $4); }
+	| '.' STR_BTRIM_P '(' opt_str_arg ')'
+		{ $$ = makeItemUnary(jpiStrBtrim, $4); }
 	;
 
 int_elem:
@@ -317,6 +329,14 @@ opt_str_arg:
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
+str_int_args:
+	str_elem ',' int_elem			{ $$ = list_make2($1, $3); }
+	;
+
+str_str_args:
+	str_elem ',' str_elem 			{ $$ = list_make2($1, $3); }
+	;
+
 key:
 	key_name						{ $$ = makeItemKey(&$1); }
 	;
@@ -357,6 +377,9 @@ key_name:
 	| TIME_TZ_P
 	| TIMESTAMP_P
 	| TIMESTAMP_TZ_P
+	| STR_LTRIM_P
+	| STR_RTRIM_P
+	| STR_BTRIM_P
 	;
 
 method:
@@ -373,6 +396,9 @@ method:
 	| INTEGER_P						{ $$ = jpiInteger; }
 	| NUMBER_P						{ $$ = jpiNumber; }
 	| STRINGFUNC_P					{ $$ = jpiStringFunc; }
+	| STR_LOWER_P					{ $$ = jpiStrLower; }
+	| STR_UPPER_P					{ $$ = jpiStrUpper; }
+	| STR_INITCAP_P					{ $$ = jpiStrInitcap; }
 	;
 %%
 
diff --git a/src/backend/utils/adt/jsonpath_scan.l b/src/backend/utils/adt/jsonpath_scan.l
index c7aab83eeb4..69c61f98500 100644
--- a/src/backend/utils/adt/jsonpath_scan.l
+++ b/src/backend/utils/adt/jsonpath_scan.l
@@ -413,8 +413,13 @@ static const JsonPathKeyword keywords[] = {
 	{4, true, TRUE_P, "true"},
 	{4, false, TYPE_P, "type"},
 	{4, false, WITH_P, "with"},
+	{5, false, STR_BTRIM_P, "btrim"},
 	{5, true, FALSE_P, "false"},
 	{5, false, FLOOR_P, "floor"},
+	{5, false, STR_LOWER_P, "lower"},
+	{5, false, STR_LTRIM_P, "ltrim"},
+	{5, false, STR_RTRIM_P, "rtrim"},
+	{5, false, STR_UPPER_P, "upper"},
 	{6, false, BIGINT_P, "bigint"},
 	{6, false, DOUBLE_P, "double"},
 	{6, false, EXISTS_P, "exists"},
@@ -425,13 +430,16 @@ static const JsonPathKeyword keywords[] = {
 	{7, false, BOOLEAN_P, "boolean"},
 	{7, false, CEILING_P, "ceiling"},
 	{7, false, DECIMAL_P, "decimal"},
+	{7, false, STR_INITCAP_P, "initcap"},
 	{7, false, INTEGER_P, "integer"},
+	{7, false, STR_REPLACE_P, "replace"},
 	{7, false, TIME_TZ_P, "time_tz"},
 	{7, false, UNKNOWN_P, "unknown"},
 	{8, false, DATETIME_P, "datetime"},
 	{8, false, KEYVALUE_P, "keyvalue"},
 	{9, false, TIMESTAMP_P, "timestamp"},
 	{10, false, LIKE_REGEX_P, "like_regex"},
+	{10,false, STR_SPLIT_PART_P, "split_part"},
 	{12, false, TIMESTAMP_TZ_P, "timestamp_tz"},
 };
 
diff --git a/src/include/utils/jsonpath.h b/src/include/utils/jsonpath.h
index 23a76d233e9..2d0c53f7b06 100644
--- a/src/include/utils/jsonpath.h
+++ b/src/include/utils/jsonpath.h
@@ -115,6 +115,14 @@ typedef enum JsonPathItemType
 	jpiTimeTz,					/* .time_tz() item method */
 	jpiTimestamp,				/* .timestamp() item method */
 	jpiTimestampTz,				/* .timestamp_tz() item method */
+	jpiStrReplace,				/* .replace() item method */
+	jpiStrLower,				/* .lower() item method */
+	jpiStrUpper,				/* .upper() item method */
+	jpiStrLtrim,				/* .ltrim() item method */
+	jpiStrRtrim,				/* .rtrim() item method */
+	jpiStrBtrim,				/* .btrim() item method */
+	jpiStrInitcap,				/* .initcap() item method */
+	jpiStrSplitPart,			/* .split_part() item method */
 } JsonPathItemType;
 
 /* XQuery regex mode flags for LIKE_REGEX predicate */
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e91a29..cea539717f9 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -2723,6 +2723,405 @@ select jsonb_path_query('"2023-08-15 12:34:56"', '$.timestamp().string()');
 (1 row)
 
 rollback;
+-- test .ltrim()
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"zzzytest"', '$.ltrim("xyz")');
+ jsonb_path_query 
+------------------
+ "test"
+(1 row)
+
+select jsonb_path_query('null', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('null', '$.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.ltrim()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('{}', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('true', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('1234', '$.ltrim().type()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim()');
+  jsonb_path_query_array  
+--------------------------
+ ["maybe  ", "yes", "no"]
+(1 row)
+
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .rtrim()
+select jsonb_path_query('"   hello   "', '$.rtrim(" ")');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+select jsonb_path_query('"testxxzx"', '$.rtrim("xyz")');
+ jsonb_path_query 
+------------------
+ "test"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+-- test .btrim()
+select jsonb_path_query('"   hello   "', '$.btrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+select jsonb_path_query('"xyxtrimyyx"', '$.btrim("xyz")');
+ jsonb_path_query 
+------------------
+ "trim"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.btrim()');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.btrim()');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+-- test .lower()
+select jsonb_path_query('null', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('null', '$.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.lower()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('{}', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.lower()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.lower()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('true', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('1234', '$.lower().type()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower()');
+ jsonb_path_query_array 
+------------------------
+ ["maybe", "yes", "no"]
+(1 row)
+
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .upper()
+select jsonb_path_query('null', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('null', '$.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.upper()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('{}', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.upper()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.upper()');
+ jsonb_path_query 
+------------------
+ "1.23AAA"
+(1 row)
+
+select jsonb_path_query('1234', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('true', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('1234', '$.upper().type()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper()');
+ jsonb_path_query_array 
+------------------------
+ ["MAYBE", "YES", "NO"]
+(1 row)
+
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .initcap()
+select jsonb_path_query('null', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('null', '$.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.initcap()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('{}', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('true', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('1234', '$.initcap().type()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('["maybe yes", "probably no"]', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "Maybe Yes"
+ "Probably No"
+(2 rows)
+
+-- Test .replace()
+select jsonb_path_query('null', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('null', '$.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('["x", "y", "z"]', '$.replace("x", "bye")');
+ jsonb_path_query 
+------------------
+ "bye"
+ "y"
+ "z"
+(3 rows)
+
+select jsonb_path_query('{}', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('"hello world"', '$.replace("hello","bye")');
+ jsonb_path_query 
+------------------
+ "bye world"
+(1 row)
+
+select jsonb_path_query('"hello world"', '$.replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
+-- Test .split_part()
+select jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)');
+ jsonb_path_query 
+------------------
+ "def"
+(1 row)
+
+select jsonb_path_query('"abc,def,ghi,jkl"', '$.split_part(",", -2)');
+ jsonb_path_query 
+------------------
+ "ghi"
+(1 row)
+
+-- Test string methods play nicely together
+select jsonb_path_query('"hello world"', '$.replace("hello","bye").upper()');
+ jsonb_path_query 
+------------------
+ "BYE WORLD"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye")');
+ jsonb_path_query 
+------------------
+ "bye world"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.upper().lower().upper().replace("HELLO", "BYE")');
+ jsonb_path_query 
+------------------
+ "BYE WORLD"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
+select jsonb_path_query('"   hElLo WorlD "', '$.btrim().lower().upper().lower().replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
 -- Test .time()
 select jsonb_path_query('null', '$.time()');
 ERROR:  jsonpath item method .time() can only be applied to a string
diff --git a/src/test/regress/expected/jsonpath.out b/src/test/regress/expected/jsonpath.out
index fd9bd755f52..a13022feabd 100644
--- a/src/test/regress/expected/jsonpath.out
+++ b/src/test/regress/expected/jsonpath.out
@@ -435,6 +435,143 @@ select '$.string()'::jsonpath;
  $.string()
 (1 row)
 
+select '$.replace("hello","bye")'::jsonpath;
+         jsonpath         
+--------------------------
+ $.replace("hello","bye")
+(1 row)
+
+select '$.lower()'::jsonpath;
+ jsonpath  
+-----------
+ $.lower()
+(1 row)
+
+select '$.upper()'::jsonpath;
+ jsonpath  
+-----------
+ $.upper()
+(1 row)
+
+select '$.lower().upper().lower().replace("hello","bye")'::jsonpath;
+                     jsonpath                     
+--------------------------------------------------
+ $.lower().upper().lower().replace("hello","bye")
+(1 row)
+
+select '$.ltrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.ltrim()
+(1 row)
+
+select '$.ltrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.ltrim("xyz")
+(1 row)
+
+select '$.rtrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.rtrim()
+(1 row)
+
+select '$.rtrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.rtrim("xyz")
+(1 row)
+
+select '$.btrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.btrim()
+(1 row)
+
+select '$.btrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.btrim("xyz")
+(1 row)
+
+select '$.initcap()'::jsonpath;
+  jsonpath   
+-------------
+ $.initcap()
+(1 row)
+
+select '$.split_part("~@~", 2)'::jsonpath;
+       jsonpath        
+-----------------------
+ $.split_part("~@~",2)
+(1 row)
+
+-- Parse errors
+select '$.replace("hello")'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.replace("hello")'::jsonpath;
+               ^
+select '$.replace()'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.replace()'::jsonpath;
+               ^
+select '$.replace("hello","bye","extra")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.replace("hello","bye","extra")'::jsonpath;
+               ^
+select '$.split_part("~@~")'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.split_part("~@~")'::jsonpath;
+               ^
+select '$.split_part()'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.split_part()'::jsonpath;
+               ^
+select '$.split_part("~@~", "hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.split_part("~@~", "hi")'::jsonpath;
+               ^
+select '$.split_part("~@~", 2, "extra")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.split_part("~@~", 2, "extra")'::jsonpath;
+               ^
+select '$.lower("hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.lower("hi")'::jsonpath;
+               ^
+select '$.upper("hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.upper("hi")'::jsonpath;
+               ^
+select '$.initcap("hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.initcap("hi")'::jsonpath;
+               ^
+select '$.ltrim(42)'::jsonpath;
+ERROR:  syntax error at or near "42" of jsonpath input
+LINE 1: select '$.ltrim(42)'::jsonpath;
+               ^
+select '$.ltrim("x", "y")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.ltrim("x", "y")'::jsonpath;
+               ^
+select '$.rtrim(42)'::jsonpath;
+ERROR:  syntax error at or near "42" of jsonpath input
+LINE 1: select '$.rtrim(42)'::jsonpath;
+               ^
+select '$.rtrim("x", "y")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.rtrim("x", "y")'::jsonpath;
+               ^
+select '$.trim(42)'::jsonpath;
+ERROR:  syntax error at or near "(" of jsonpath input
+LINE 1: select '$.trim(42)'::jsonpath;
+               ^
+select '$.trim("x", "y")'::jsonpath;
+ERROR:  syntax error at or near "(" of jsonpath input
+LINE 1: select '$.trim("x", "y")'::jsonpath;
+               ^
 select '$.time()'::jsonpath;
  jsonpath 
 ----------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a5269..8169719343e 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -623,6 +623,115 @@ select jsonb_path_query('"2023-08-15 12:34:56 +5:30"', '$.timestamp_tz().string(
 select jsonb_path_query('"2023-08-15 12:34:56"', '$.timestamp().string()');
 rollback;
 
+-- test .ltrim()
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+select jsonb_path_query('"   hello   "', '$.ltrim()');
+select jsonb_path_query('"zzzytest"', '$.ltrim("xyz")');
+select jsonb_path_query('null', '$.ltrim()');
+select jsonb_path_query('null', '$.ltrim()', silent => true);
+select jsonb_path_query('[]', '$.ltrim()');
+select jsonb_path_query('[]', 'strict $.ltrim()');
+select jsonb_path_query('{}', '$.ltrim()');
+select jsonb_path_query('[]', 'strict $.ltrim()', silent => true);
+select jsonb_path_query('{}', '$.ltrim()', silent => true);
+select jsonb_path_query('1.23', '$.ltrim()');
+select jsonb_path_query('"1.23"', '$.ltrim()');
+select jsonb_path_query('"1.23aaa"', '$.ltrim()');
+select jsonb_path_query('1234', '$.ltrim()');
+select jsonb_path_query('true', '$.ltrim()');
+select jsonb_path_query('1234', '$.ltrim().type()');
+select jsonb_path_query('[2, true]', '$.ltrim()');
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim()');
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim().type()');
+
+-- test .rtrim()
+select jsonb_path_query('"   hello   "', '$.rtrim(" ")');
+select jsonb_path_query('"testxxzx"', '$.rtrim("xyz")');
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+
+-- test .btrim()
+select jsonb_path_query('"   hello   "', '$.btrim(" ")');
+select jsonb_path_query('"xyxtrimyyx"', '$.btrim("xyz")');
+select jsonb_path_query('"   hello   "', '$.btrim()');
+select jsonb_path_query('"   hello   "', '$.btrim()');
+
+-- test .lower()
+select jsonb_path_query('null', '$.lower()');
+select jsonb_path_query('null', '$.lower()', silent => true);
+select jsonb_path_query('[]', '$.lower()');
+select jsonb_path_query('[]', 'strict $.lower()');
+select jsonb_path_query('{}', '$.lower()');
+select jsonb_path_query('[]', 'strict $.lower()', silent => true);
+select jsonb_path_query('{}', '$.lower()', silent => true);
+select jsonb_path_query('1.23', '$.lower()');
+select jsonb_path_query('"1.23"', '$.lower()');
+select jsonb_path_query('"1.23aaa"', '$.lower()');
+select jsonb_path_query('1234', '$.lower()');
+select jsonb_path_query('true', '$.lower()');
+select jsonb_path_query('1234', '$.lower().type()');
+select jsonb_path_query('[2, true]', '$.lower()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower().type()');
+
+-- test .upper()
+select jsonb_path_query('null', '$.upper()');
+select jsonb_path_query('null', '$.upper()', silent => true);
+select jsonb_path_query('[]', '$.upper()');
+select jsonb_path_query('[]', 'strict $.upper()');
+select jsonb_path_query('{}', '$.upper()');
+select jsonb_path_query('[]', 'strict $.upper()', silent => true);
+select jsonb_path_query('{}', '$.upper()', silent => true);
+select jsonb_path_query('1.23', '$.upper()');
+select jsonb_path_query('"1.23"', '$.upper()');
+select jsonb_path_query('"1.23aaa"', '$.upper()');
+select jsonb_path_query('1234', '$.upper()');
+select jsonb_path_query('true', '$.upper()');
+select jsonb_path_query('1234', '$.upper().type()');
+select jsonb_path_query('[2, true]', '$.upper()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper().type()');
+
+-- test .initcap()
+select jsonb_path_query('null', '$.initcap()');
+select jsonb_path_query('null', '$.initcap()', silent => true);
+select jsonb_path_query('[]', '$.initcap()');
+select jsonb_path_query('[]', 'strict $.initcap()');
+select jsonb_path_query('{}', '$.initcap()');
+select jsonb_path_query('[]', 'strict $.initcap()', silent => true);
+select jsonb_path_query('{}', '$.initcap()', silent => true);
+select jsonb_path_query('1.23', '$.initcap()');
+select jsonb_path_query('"1.23"', '$.initcap()');
+select jsonb_path_query('"1.23aaa"', '$.initcap()');
+select jsonb_path_query('1234', '$.initcap()');
+select jsonb_path_query('true', '$.initcap()');
+select jsonb_path_query('1234', '$.initcap().type()');
+select jsonb_path_query('[2, true]', '$.initcap()');
+select jsonb_path_query('["maybe yes", "probably no"]', '$.initcap()');
+
+-- Test .replace()
+select jsonb_path_query('null', '$.replace("x", "bye")');
+select jsonb_path_query('null', '$.replace("x", "bye")', silent => true);
+select jsonb_path_query('["x", "y", "z"]', '$.replace("x", "bye")');
+select jsonb_path_query('{}', '$.replace("x", "bye")');
+select jsonb_path_query('[]', 'strict $.replace("x", "bye")', silent => true);
+select jsonb_path_query('{}', '$.replace("x", "bye")', silent => true);
+select jsonb_path_query('1.23', '$.replace("x", "bye")');
+select jsonb_path_query('"hello world"', '$.replace("hello","bye")');
+select jsonb_path_query('"hello world"', '$.replace("hello","bye") starts with "bye"');
+
+-- Test .split_part()
+select jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)');
+select jsonb_path_query('"abc,def,ghi,jkl"', '$.split_part(",", -2)');
+
+-- Test string methods play nicely together
+select jsonb_path_query('"hello world"', '$.replace("hello","bye").upper()');
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye")');
+select jsonb_path_query('"hElLo WorlD"', '$.upper().lower().upper().replace("HELLO", "BYE")');
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye") starts with "bye"');
+select jsonb_path_query('"   hElLo WorlD "', '$.btrim().lower().upper().lower().replace("hello","bye") starts with "bye"');
+
 -- Test .time()
 select jsonb_path_query('null', '$.time()');
 select jsonb_path_query('true', '$.time()');
diff --git a/src/test/regress/sql/jsonpath.sql b/src/test/regress/sql/jsonpath.sql
index 61a5270d4e8..7dd2e57e7a6 100644
--- a/src/test/regress/sql/jsonpath.sql
+++ b/src/test/regress/sql/jsonpath.sql
@@ -78,6 +78,37 @@ select '$.boolean()'::jsonpath;
 select '$.date()'::jsonpath;
 select '$.decimal(4,2)'::jsonpath;
 select '$.string()'::jsonpath;
+select '$.replace("hello","bye")'::jsonpath;
+select '$.lower()'::jsonpath;
+select '$.upper()'::jsonpath;
+select '$.lower().upper().lower().replace("hello","bye")'::jsonpath;
+select '$.ltrim()'::jsonpath;
+select '$.ltrim("xyz")'::jsonpath;
+select '$.rtrim()'::jsonpath;
+select '$.rtrim("xyz")'::jsonpath;
+select '$.btrim()'::jsonpath;
+select '$.btrim("xyz")'::jsonpath;
+select '$.initcap()'::jsonpath;
+select '$.split_part("~@~", 2)'::jsonpath;
+
+-- Parse errors
+select '$.replace("hello")'::jsonpath;
+select '$.replace()'::jsonpath;
+select '$.replace("hello","bye","extra")'::jsonpath;
+select '$.split_part("~@~")'::jsonpath;
+select '$.split_part()'::jsonpath;
+select '$.split_part("~@~", "hi")'::jsonpath;
+select '$.split_part("~@~", 2, "extra")'::jsonpath;
+select '$.lower("hi")'::jsonpath;
+select '$.upper("hi")'::jsonpath;
+select '$.initcap("hi")'::jsonpath;
+select '$.ltrim(42)'::jsonpath;
+select '$.ltrim("x", "y")'::jsonpath;
+select '$.rtrim(42)'::jsonpath;
+select '$.rtrim("x", "y")'::jsonpath;
+select '$.trim(42)'::jsonpath;
+select '$.trim("x", "y")'::jsonpath;
+
 select '$.time()'::jsonpath;
 select '$.time(6)'::jsonpath;
 select '$.time_tz()'::jsonpath;
-- 
2.49.0

From 0db127dd34b0955f9533977103b8a9f7cc78bbf0 Mon Sep 17 00:00:00 2001
From: Florents Tselai <florents.tselai@gmail.com>
Date: Thu, 10 Jul 2025 19:01:34 -0400
Subject: [PATCH v11 2/2] Add additional jsonpath string methods

Add the following jsonpath methods:

*   l/r/btrim()
*   lower(), upper()
*   initcap()
*   replace()
*   split_part()

Each simply dispatches to the standard string processing functions.
These depend on the locale, but since it's set at `initdb`, they can be
considered immutable and therefore allowed in any jsonpath expression.
---
 doc/src/sgml/func.sgml                       | 140 +++++++
 src/backend/utils/adt/jsonpath.c             | 117 +++++-
 src/backend/utils/adt/jsonpath_exec.c        | 207 ++++++++++
 src/backend/utils/adt/jsonpath_gram.y        |  28 +-
 src/backend/utils/adt/jsonpath_scan.l        |   8 +
 src/include/utils/jsonpath.h                 |   8 +
 src/test/regress/expected/jsonb_jsonpath.out | 399 +++++++++++++++++++
 src/test/regress/expected/jsonpath.out       | 137 +++++++
 src/test/regress/sql/jsonb_jsonpath.sql      | 109 +++++
 src/test/regress/sql/jsonpath.sql            |  31 ++
 10 files changed, 1179 insertions(+), 5 deletions(-)

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index c28aa71f570..23710921869 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -18637,6 +18637,146 @@ ERROR:  jsonpath member accessor can only be applied to an object
         <returnvalue>[{"id": 0, "key": "x", "value": "20"}, {"id": 0, "key": "y", "value": 32}]</returnvalue>
        </para></entry>
       </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>lower()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String converted to all lower case according to the rules of the database's locale.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"TOM"', '$.lower()')</literal>
+        <returnvalue>"tom"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>upper()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String converted to all upper case according to the rules of the database's locale.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"tom"', '$.upper()')</literal>
+        <returnvalue>"TOM"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>initcap()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the first letter of each word converted to upper case
+        according to the rules of the database's locale. Words are sequences
+        of alphanumeric characters separated by non-alphanumeric characters.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"hi THOMAS"', '$.initcap()')</literal>
+        <returnvalue>"Hi Thomas"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>replace(<replaceable>from</replaceable>, <replaceable>to</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with all occurrences of substring from replaced with substring to.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"abcdefabcdef"', '$.replace("cd", "XX")')</literal>
+        <returnvalue>"abXXefabXXef"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>split_part(<replaceable>delimiter</replaceable>, <replaceable>n</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String split at occurrences of <replaceable>delimiter</replaceable>
+        and returns the <replaceable>n</replaceable>'th field (counting from
+        one) or, when <replaceable>n</replaceable> is negative, returns the
+        |<replaceable>n</replaceable>|'th-from-last field.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)')</literal>
+        <returnvalue>"def"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"abc,def,ghi,jkl"', '$.split_part(",", 2)')</literal>
+        <returnvalue>"ghi"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>ltrim(<replaceable>characters</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the longest string containing only spaces or the
+        characters in <replaceable>characters</replaceable> removed from the
+        start of <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal> jsonb_path_query('"  hello"', '$.ltrim()')</literal>
+        <returnvalue>"hello"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"zzzytest"', '$.ltrim("xyz")')</literal>
+        <returnvalue>"test"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>rtrim([ <replaceable>characters</replaceable> ])</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the longest string containing only spaces or the
+        characters in <replaceable>characters</replaceable> removed from the
+        end of <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"hello  "', '$.rtrim()')</literal>
+        <returnvalue>"hello"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"testxxzx"', '$.rtrim("xyz")')</literal>
+        <returnvalue>"test"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>btrim([ <replaceable>characters</replaceable> ])</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the longest string containing only spaces or the
+        characters in <replaceable>characters</replaceable> removed from the
+        start and end of <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"  hello  "', '$.btrim()')</literal>
+        <returnvalue>"hello"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"xyxtrimyyx"', '$.btrim("xyz")')</literal>
+        <returnvalue>"trim"</returnvalue>
+       </para></entry>
+      </row>
+
      </tbody>
     </tgroup>
    </table>
diff --git a/src/backend/utils/adt/jsonpath.c b/src/backend/utils/adt/jsonpath.c
index 762f7e8a09d..f3f2119a4a8 100644
--- a/src/backend/utils/adt/jsonpath.c
+++ b/src/backend/utils/adt/jsonpath.c
@@ -298,6 +298,8 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 		case jpiMod:
 		case jpiStartsWith:
 		case jpiDecimal:
+		case jpiStrReplace:
+		case jpiStrSplitPart:
 			{
 				/*
 				 * First, reserve place for left/right arg's positions, then
@@ -362,6 +364,9 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 		case jpiTimeTz:
 		case jpiTimestamp:
 		case jpiTimestampTz:
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
 			{
 				int32		arg = reserveSpaceForItemPointer(buf);
 
@@ -457,6 +462,9 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 		case jpiInteger:
 		case jpiNumber:
 		case jpiStringFunc:
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrInitcap:
 			break;
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", item->type);
@@ -831,6 +839,60 @@ printJsonPathItem(StringInfo buf, JsonPathItem *v, bool inKey,
 			}
 			appendStringInfoChar(buf, ')');
 			break;
+		case jpiStrReplace:
+			appendStringInfoString(buf, ".replace(");
+			jspGetLeftArg(v, &elem);
+			printJsonPathItem(buf, &elem, false, false);
+			appendStringInfoChar(buf, ',');
+			jspGetRightArg(v, &elem);
+			printJsonPathItem(buf, &elem, false, false);
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrSplitPart:
+			appendStringInfoString(buf, ".split_part(");
+			jspGetLeftArg(v, &elem);
+			printJsonPathItem(buf, &elem, false, false);
+			appendStringInfoChar(buf, ',');
+			jspGetRightArg(v, &elem);
+			printJsonPathItem(buf, &elem, false, false);
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrLower:
+			appendStringInfoString(buf, ".lower()");
+			break;
+		case jpiStrUpper:
+			appendStringInfoString(buf, ".upper()");
+			break;
+		case jpiStrInitcap:
+			appendStringInfoString(buf, ".initcap()");
+			break;
+		case jpiStrLtrim:
+			appendStringInfoString(buf, ".ltrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrRtrim:
+			appendStringInfoString(buf, ".rtrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrBtrim:
+			appendStringInfoString(buf, ".btrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", v->type);
 	}
@@ -906,6 +968,12 @@ jspOperationName(JsonPathItemType type)
 			return "number";
 		case jpiStringFunc:
 			return "string";
+		case jpiStrReplace:
+			return "replace";
+		case jpiStrLower:
+			return "lower";
+		case jpiStrUpper:
+			return "upper";
 		case jpiTime:
 			return "time";
 		case jpiTimeTz:
@@ -914,6 +982,16 @@ jspOperationName(JsonPathItemType type)
 			return "timestamp";
 		case jpiTimestampTz:
 			return "timestamp_tz";
+		case jpiStrLtrim:
+			return "ltrim";
+		case jpiStrRtrim:
+			return "rtrim";
+		case jpiStrBtrim:
+			return "btrim";
+		case jpiStrInitcap:
+			return "initcap";
+		case jpiStrSplitPart:
+			return "split_part";
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", type);
 			return NULL;
@@ -1016,6 +1094,9 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 		case jpiInteger:
 		case jpiNumber:
 		case jpiStringFunc:
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrInitcap:
 			break;
 		case jpiString:
 		case jpiKey:
@@ -1041,6 +1122,8 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 		case jpiMod:
 		case jpiStartsWith:
 		case jpiDecimal:
+		case jpiStrReplace:
+		case jpiStrSplitPart:
 			read_int32(v->content.args.left, base, pos);
 			read_int32(v->content.args.right, base, pos);
 			break;
@@ -1055,6 +1138,9 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 		case jpiTimeTz:
 		case jpiTimestamp:
 		case jpiTimestampTz:
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
 			read_int32(v->content.arg, base, pos);
 			break;
 		case jpiIndexArray:
@@ -1090,7 +1176,10 @@ jspGetArg(JsonPathItem *v, JsonPathItem *a)
 		   v->type == jpiTime ||
 		   v->type == jpiTimeTz ||
 		   v->type == jpiTimestamp ||
-		   v->type == jpiTimestampTz);
+		   v->type == jpiTimestampTz ||
+		   v->type == jpiStrLtrim ||
+		   v->type == jpiStrRtrim ||
+		   v->type == jpiStrBtrim);
 
 	jspInitByBuffer(a, v->base, v->content.arg);
 }
@@ -1149,10 +1238,18 @@ jspGetNext(JsonPathItem *v, JsonPathItem *a)
 			   v->type == jpiInteger ||
 			   v->type == jpiNumber ||
 			   v->type == jpiStringFunc ||
+			   v->type == jpiStrReplace ||
+			   v->type == jpiStrLower ||
+			   v->type == jpiStrUpper ||
 			   v->type == jpiTime ||
 			   v->type == jpiTimeTz ||
 			   v->type == jpiTimestamp ||
-			   v->type == jpiTimestampTz);
+			   v->type == jpiTimestampTz ||
+			   v->type == jpiStrLtrim ||
+			   v->type == jpiStrRtrim ||
+			   v->type == jpiStrBtrim ||
+			   v->type == jpiStrInitcap ||
+			   v->type == jpiStrSplitPart);
 
 		if (a)
 			jspInitByBuffer(a, v->base, v->nextPos);
@@ -1179,7 +1276,9 @@ jspGetLeftArg(JsonPathItem *v, JsonPathItem *a)
 		   v->type == jpiDiv ||
 		   v->type == jpiMod ||
 		   v->type == jpiStartsWith ||
-		   v->type == jpiDecimal);
+		   v->type == jpiDecimal ||
+		   v->type == jpiStrReplace ||
+		   v->type == jpiStrSplitPart);
 
 	jspInitByBuffer(a, v->base, v->content.args.left);
 }
@@ -1201,7 +1300,9 @@ jspGetRightArg(JsonPathItem *v, JsonPathItem *a)
 		   v->type == jpiDiv ||
 		   v->type == jpiMod ||
 		   v->type == jpiStartsWith ||
-		   v->type == jpiDecimal);
+		   v->type == jpiDecimal ||
+		   v->type == jpiStrReplace ||
+		   v->type == jpiStrSplitPart);
 
 	jspInitByBuffer(a, v->base, v->content.args.right);
 }
@@ -1501,6 +1602,14 @@ jspIsMutableWalker(JsonPathItem *jpi, struct JsonPathMutableContext *cxt)
 			case jpiInteger:
 			case jpiNumber:
 			case jpiStringFunc:
+			case jpiStrReplace:
+			case jpiStrLower:
+			case jpiStrUpper:
+			case jpiStrLtrim:
+			case jpiStrRtrim:
+			case jpiStrBtrim:
+			case jpiStrInitcap:
+			case jpiStrSplitPart:
 				status = jpdsNonDateTime;
 				break;
 
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index dbab24737ef..a8161f2f7fa 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -301,6 +301,8 @@ static JsonPathExecResult executeNumericItemMethod(JsonPathExecContext *cxt,
 												   JsonValueList *found);
 static JsonPathExecResult executeDateTimeMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
 												JsonbValue *jb, JsonValueList *found);
+static JsonPathExecResult executeStringInternalMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
+													  JsonbValue *jb, JsonValueList *found);
 static JsonPathExecResult executeKeyValueMethod(JsonPathExecContext *cxt,
 												JsonPathItem *jsp, JsonbValue *jb, JsonValueList *found);
 static JsonPathExecResult appendBoolResult(JsonPathExecContext *cxt,
@@ -1659,6 +1661,23 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
 			}
 			break;
 
+		case jpiStrLtrim:
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrReplace:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
+		case jpiStrInitcap:
+		case jpiStrSplitPart:
+			{
+				if (unwrap && JsonbType(jb) == jbvArray)
+					return executeItemUnwrapTargetArray(cxt, jsp, jb, found, false);
+
+				return executeStringInternalMethod(cxt, jsp, jb, found);
+			}
+			break;
+
+
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", jsp->type);
 	}
@@ -2792,6 +2811,194 @@ executeDateTimeMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
 	return executeNextItem(cxt, jsp, &elem, jb, found, hasNext);
 }
 
+/*
+ * Implementation of .upper(), lower() et. al. methods,
+ * that forward their actual implementation to internal functions.
+ */
+static JsonPathExecResult
+executeStringInternalMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
+							JsonbValue *jb, JsonValueList *found)
+{
+	JsonbValue	jbvbuf;
+	bool		hasNext;
+	JsonPathExecResult res = jperNotFound;
+	JsonPathItem elem;
+	Datum		str;			/* Datum representation for the current string
+								 * value. The first argument to internal
+								 * functions */
+	char	   *tmp = NULL;
+	char	   *resStr = NULL;
+
+	Assert(jsp->type == jpiStrLower ||
+		   jsp->type == jpiStrUpper ||
+		   jsp->type == jpiStrReplace ||
+		   jsp->type == jpiStrLtrim ||
+		   jsp->type == jpiStrRtrim ||
+		   jsp->type == jpiStrBtrim ||
+		   jsp->type == jpiStrInitcap ||
+		   jsp->type == jpiStrSplitPart);
+
+	if (!(jb = getScalar(jb, jbvString)))
+		RETURN_ERROR(ereport(ERROR,
+							 (errcode(ERRCODE_INVALID_ARGUMENT_FOR_SQL_JSON_DATETIME_FUNCTION),
+							  errmsg("jsonpath item method .%s() can only be applied to a string",
+									 jspOperationName(jsp->type)))));
+
+	tmp = pnstrdup(jb->val.string.val, jb->val.string.len);
+	str = CStringGetTextDatum(tmp);
+
+	/* Internal string functions that accept no arguments */
+	switch (jsp->type)
+	{
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
+			{
+				char	   *characters_str;
+				int			characters_len;
+				PGFunction	func = NULL;
+
+				if (jsp->content.arg)
+				{
+					switch (jsp->type)
+					{
+						case jpiStrLtrim:
+							func = ltrim;
+							break;
+						case jpiStrRtrim:
+							func = rtrim;
+							break;
+						case jpiStrBtrim:
+							func = btrim;
+							break;
+						default:;
+					}
+					jspGetArg(jsp, &elem);
+					if (elem.type != jpiString)
+						elog(ERROR, "invalid jsonpath item type for .%s() argument", jspOperationName(jsp->type));
+
+					characters_str = jspGetString(&elem, &characters_len);
+					resStr = TextDatumGetCString(DirectFunctionCall2Coll(func,
+																		 DEFAULT_COLLATION_OID, str,
+																		 CStringGetTextDatum(characters_str)));
+					break;
+				}
+
+				switch (jsp->type)
+				{
+					case jpiStrLtrim:
+						func = ltrim1;
+						break;
+					case jpiStrRtrim:
+						func = rtrim1;
+						break;
+					case jpiStrBtrim:
+						func = btrim1;
+						break;
+					default:;
+				}
+				resStr = TextDatumGetCString(DirectFunctionCall1Coll(func,
+																	 DEFAULT_COLLATION_OID, str));
+				break;
+			}
+
+		case jpiStrLower:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(lower, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiStrUpper:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(upper, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiStrInitcap:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(initcap, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiStrReplace:
+			{
+				char	   *from_str,
+						   *to_str;
+				int			from_len,
+							to_len;
+
+				jspGetLeftArg(jsp, &elem);
+				if (elem.type != jpiString)
+					elog(ERROR, "invalid jsonpath item type for .replace() from");
+
+				from_str = jspGetString(&elem, &from_len);
+
+				jspGetRightArg(jsp, &elem);
+				if (elem.type != jpiString)
+					elog(ERROR, "invalid jsonpath item type for .replace() to");
+
+				to_str = jspGetString(&elem, &to_len);
+
+				resStr = TextDatumGetCString(DirectFunctionCall3Coll(replace_text,
+																	 C_COLLATION_OID,
+																	 CStringGetTextDatum(tmp),
+																	 CStringGetTextDatum(from_str),
+																	 CStringGetTextDatum(to_str)));
+				break;
+			}
+		case jpiStrSplitPart:
+			{
+				char	   *from_str;
+				Numeric		n;
+				int			from_len;
+
+				jspGetLeftArg(jsp, &elem);
+				if (elem.type != jpiString)
+					elog(ERROR, "invalid jsonpath item type for .split_part()");
+
+				from_str = jspGetString(&elem, &from_len);
+
+				jspGetRightArg(jsp, &elem);
+				if (elem.type != jpiNumeric)
+					elog(ERROR, "invalid jsonpath item type for .split_part()");
+
+				n = jspGetNumeric(&elem);
+
+				resStr = TextDatumGetCString(DirectFunctionCall3Coll(split_part,
+																	 C_COLLATION_OID,
+																	 CStringGetTextDatum(tmp),
+																	 CStringGetTextDatum(from_str),
+																	 DirectFunctionCall1(numeric_int8, NumericGetDatum(n))));
+				break;
+			}
+		default:
+			elog(ERROR, "unsupported jsonpath item type: %d", jsp->type);
+	}
+
+	if (resStr)
+		res = jperOk;
+
+	hasNext = jspGetNext(jsp, &elem);
+
+	if (!hasNext && !found)
+		return res;
+
+	jb = hasNext ? &jbvbuf : palloc(sizeof(*jb));
+
+	/* Create the appropriate jb value to return */
+	switch (jsp->type)
+	{
+			/* Cases for functions that return text */
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrReplace:
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
+		case jpiStrInitcap:
+		case jpiStrSplitPart:
+			jb->type = jbvString;
+			jb->val.string.val = resStr;
+			jb->val.string.len = strlen(jb->val.string.val);
+		default:
+			;
+			/* cant' happen */
+	}
+
+	return executeNextItem(cxt, jsp, &elem, jb, found, hasNext);
+}
+
 /*
  * Implementation of .keyvalue() method.
  *
diff --git a/src/backend/utils/adt/jsonpath_gram.y b/src/backend/utils/adt/jsonpath_gram.y
index 0b16cec18c4..53bf779e152 100644
--- a/src/backend/utils/adt/jsonpath_gram.y
+++ b/src/backend/utils/adt/jsonpath_gram.y
@@ -86,6 +86,8 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 %token	<str>		DATETIME_P
 %token	<str>		BIGINT_P BOOLEAN_P DATE_P DECIMAL_P INTEGER_P NUMBER_P
 %token	<str>		STRINGFUNC_P TIME_P TIME_TZ_P TIMESTAMP_P TIMESTAMP_TZ_P
+%token	<str>		STR_REPLACE_P STR_LOWER_P STR_UPPER_P STR_LTRIM_P STR_RTRIM_P STR_BTRIM_P
+					STR_INITCAP_P STR_SPLIT_PART_P
 
 %type	<result>	result
 
@@ -95,7 +97,7 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 					str_elem opt_str_arg int_elem
 					uint_elem opt_uint_arg
 
-%type	<elems>		accessor_expr int_list opt_int_list
+%type	<elems>		accessor_expr int_list opt_int_list str_int_args str_str_args
 
 %type	<indexs>	index_list
 
@@ -278,6 +280,16 @@ accessor_op:
 		{ $$ = makeItemUnary(jpiTimestamp, $4); }
 	| '.' TIMESTAMP_TZ_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimestampTz, $4); }
+	| '.' STR_REPLACE_P '(' str_str_args ')'
+		{ $$ = makeItemBinary(jpiStrReplace, linitial($4), lsecond($4)); }
+	| '.' STR_SPLIT_PART_P '(' str_int_args ')'
+		{ $$ = makeItemBinary(jpiStrSplitPart, linitial($4), lsecond($4)); }
+	| '.' STR_LTRIM_P '(' opt_str_arg ')'
+		{ $$ = makeItemUnary(jpiStrLtrim, $4); }
+	| '.' STR_RTRIM_P '(' opt_str_arg ')'
+		{ $$ = makeItemUnary(jpiStrRtrim, $4); }
+	| '.' STR_BTRIM_P '(' opt_str_arg ')'
+		{ $$ = makeItemUnary(jpiStrBtrim, $4); }
 	;
 
 int_elem:
@@ -317,6 +329,14 @@ opt_str_arg:
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
+str_int_args:
+	str_elem ',' int_elem			{ $$ = list_make2($1, $3); }
+	;
+
+str_str_args:
+	str_elem ',' str_elem 			{ $$ = list_make2($1, $3); }
+	;
+
 key:
 	key_name						{ $$ = makeItemKey(&$1); }
 	;
@@ -357,6 +377,9 @@ key_name:
 	| TIME_TZ_P
 	| TIMESTAMP_P
 	| TIMESTAMP_TZ_P
+	| STR_LTRIM_P
+	| STR_RTRIM_P
+	| STR_BTRIM_P
 	;
 
 method:
@@ -373,6 +396,9 @@ method:
 	| INTEGER_P						{ $$ = jpiInteger; }
 	| NUMBER_P						{ $$ = jpiNumber; }
 	| STRINGFUNC_P					{ $$ = jpiStringFunc; }
+	| STR_LOWER_P					{ $$ = jpiStrLower; }
+	| STR_UPPER_P					{ $$ = jpiStrUpper; }
+	| STR_INITCAP_P					{ $$ = jpiStrInitcap; }
 	;
 %%
 
diff --git a/src/backend/utils/adt/jsonpath_scan.l b/src/backend/utils/adt/jsonpath_scan.l
index c7aab83eeb4..69c61f98500 100644
--- a/src/backend/utils/adt/jsonpath_scan.l
+++ b/src/backend/utils/adt/jsonpath_scan.l
@@ -413,8 +413,13 @@ static const JsonPathKeyword keywords[] = {
 	{4, true, TRUE_P, "true"},
 	{4, false, TYPE_P, "type"},
 	{4, false, WITH_P, "with"},
+	{5, false, STR_BTRIM_P, "btrim"},
 	{5, true, FALSE_P, "false"},
 	{5, false, FLOOR_P, "floor"},
+	{5, false, STR_LOWER_P, "lower"},
+	{5, false, STR_LTRIM_P, "ltrim"},
+	{5, false, STR_RTRIM_P, "rtrim"},
+	{5, false, STR_UPPER_P, "upper"},
 	{6, false, BIGINT_P, "bigint"},
 	{6, false, DOUBLE_P, "double"},
 	{6, false, EXISTS_P, "exists"},
@@ -425,13 +430,16 @@ static const JsonPathKeyword keywords[] = {
 	{7, false, BOOLEAN_P, "boolean"},
 	{7, false, CEILING_P, "ceiling"},
 	{7, false, DECIMAL_P, "decimal"},
+	{7, false, STR_INITCAP_P, "initcap"},
 	{7, false, INTEGER_P, "integer"},
+	{7, false, STR_REPLACE_P, "replace"},
 	{7, false, TIME_TZ_P, "time_tz"},
 	{7, false, UNKNOWN_P, "unknown"},
 	{8, false, DATETIME_P, "datetime"},
 	{8, false, KEYVALUE_P, "keyvalue"},
 	{9, false, TIMESTAMP_P, "timestamp"},
 	{10, false, LIKE_REGEX_P, "like_regex"},
+	{10,false, STR_SPLIT_PART_P, "split_part"},
 	{12, false, TIMESTAMP_TZ_P, "timestamp_tz"},
 };
 
diff --git a/src/include/utils/jsonpath.h b/src/include/utils/jsonpath.h
index 23a76d233e9..2d0c53f7b06 100644
--- a/src/include/utils/jsonpath.h
+++ b/src/include/utils/jsonpath.h
@@ -115,6 +115,14 @@ typedef enum JsonPathItemType
 	jpiTimeTz,					/* .time_tz() item method */
 	jpiTimestamp,				/* .timestamp() item method */
 	jpiTimestampTz,				/* .timestamp_tz() item method */
+	jpiStrReplace,				/* .replace() item method */
+	jpiStrLower,				/* .lower() item method */
+	jpiStrUpper,				/* .upper() item method */
+	jpiStrLtrim,				/* .ltrim() item method */
+	jpiStrRtrim,				/* .rtrim() item method */
+	jpiStrBtrim,				/* .btrim() item method */
+	jpiStrInitcap,				/* .initcap() item method */
+	jpiStrSplitPart,			/* .split_part() item method */
 } JsonPathItemType;
 
 /* XQuery regex mode flags for LIKE_REGEX predicate */
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e91a29..cea539717f9 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -2723,6 +2723,405 @@ select jsonb_path_query('"2023-08-15 12:34:56"', '$.timestamp().string()');
 (1 row)
 
 rollback;
+-- test .ltrim()
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"zzzytest"', '$.ltrim("xyz")');
+ jsonb_path_query 
+------------------
+ "test"
+(1 row)
+
+select jsonb_path_query('null', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('null', '$.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.ltrim()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('{}', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('true', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('1234', '$.ltrim().type()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim()');
+  jsonb_path_query_array  
+--------------------------
+ ["maybe  ", "yes", "no"]
+(1 row)
+
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .rtrim()
+select jsonb_path_query('"   hello   "', '$.rtrim(" ")');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+select jsonb_path_query('"testxxzx"', '$.rtrim("xyz")');
+ jsonb_path_query 
+------------------
+ "test"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+-- test .btrim()
+select jsonb_path_query('"   hello   "', '$.btrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+select jsonb_path_query('"xyxtrimyyx"', '$.btrim("xyz")');
+ jsonb_path_query 
+------------------
+ "trim"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.btrim()');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.btrim()');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+-- test .lower()
+select jsonb_path_query('null', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('null', '$.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.lower()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('{}', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.lower()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.lower()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('true', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('1234', '$.lower().type()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower()');
+ jsonb_path_query_array 
+------------------------
+ ["maybe", "yes", "no"]
+(1 row)
+
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .upper()
+select jsonb_path_query('null', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('null', '$.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.upper()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('{}', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.upper()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.upper()');
+ jsonb_path_query 
+------------------
+ "1.23AAA"
+(1 row)
+
+select jsonb_path_query('1234', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('true', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('1234', '$.upper().type()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper()');
+ jsonb_path_query_array 
+------------------------
+ ["MAYBE", "YES", "NO"]
+(1 row)
+
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .initcap()
+select jsonb_path_query('null', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('null', '$.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.initcap()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('{}', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('true', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('1234', '$.initcap().type()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('["maybe yes", "probably no"]', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "Maybe Yes"
+ "Probably No"
+(2 rows)
+
+-- Test .replace()
+select jsonb_path_query('null', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('null', '$.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('["x", "y", "z"]', '$.replace("x", "bye")');
+ jsonb_path_query 
+------------------
+ "bye"
+ "y"
+ "z"
+(3 rows)
+
+select jsonb_path_query('{}', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('"hello world"', '$.replace("hello","bye")');
+ jsonb_path_query 
+------------------
+ "bye world"
+(1 row)
+
+select jsonb_path_query('"hello world"', '$.replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
+-- Test .split_part()
+select jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)');
+ jsonb_path_query 
+------------------
+ "def"
+(1 row)
+
+select jsonb_path_query('"abc,def,ghi,jkl"', '$.split_part(",", -2)');
+ jsonb_path_query 
+------------------
+ "ghi"
+(1 row)
+
+-- Test string methods play nicely together
+select jsonb_path_query('"hello world"', '$.replace("hello","bye").upper()');
+ jsonb_path_query 
+------------------
+ "BYE WORLD"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye")');
+ jsonb_path_query 
+------------------
+ "bye world"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.upper().lower().upper().replace("HELLO", "BYE")');
+ jsonb_path_query 
+------------------
+ "BYE WORLD"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
+select jsonb_path_query('"   hElLo WorlD "', '$.btrim().lower().upper().lower().replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
 -- Test .time()
 select jsonb_path_query('null', '$.time()');
 ERROR:  jsonpath item method .time() can only be applied to a string
diff --git a/src/test/regress/expected/jsonpath.out b/src/test/regress/expected/jsonpath.out
index fd9bd755f52..a13022feabd 100644
--- a/src/test/regress/expected/jsonpath.out
+++ b/src/test/regress/expected/jsonpath.out
@@ -435,6 +435,143 @@ select '$.string()'::jsonpath;
  $.string()
 (1 row)
 
+select '$.replace("hello","bye")'::jsonpath;
+         jsonpath         
+--------------------------
+ $.replace("hello","bye")
+(1 row)
+
+select '$.lower()'::jsonpath;
+ jsonpath  
+-----------
+ $.lower()
+(1 row)
+
+select '$.upper()'::jsonpath;
+ jsonpath  
+-----------
+ $.upper()
+(1 row)
+
+select '$.lower().upper().lower().replace("hello","bye")'::jsonpath;
+                     jsonpath                     
+--------------------------------------------------
+ $.lower().upper().lower().replace("hello","bye")
+(1 row)
+
+select '$.ltrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.ltrim()
+(1 row)
+
+select '$.ltrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.ltrim("xyz")
+(1 row)
+
+select '$.rtrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.rtrim()
+(1 row)
+
+select '$.rtrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.rtrim("xyz")
+(1 row)
+
+select '$.btrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.btrim()
+(1 row)
+
+select '$.btrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.btrim("xyz")
+(1 row)
+
+select '$.initcap()'::jsonpath;
+  jsonpath   
+-------------
+ $.initcap()
+(1 row)
+
+select '$.split_part("~@~", 2)'::jsonpath;
+       jsonpath        
+-----------------------
+ $.split_part("~@~",2)
+(1 row)
+
+-- Parse errors
+select '$.replace("hello")'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.replace("hello")'::jsonpath;
+               ^
+select '$.replace()'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.replace()'::jsonpath;
+               ^
+select '$.replace("hello","bye","extra")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.replace("hello","bye","extra")'::jsonpath;
+               ^
+select '$.split_part("~@~")'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.split_part("~@~")'::jsonpath;
+               ^
+select '$.split_part()'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.split_part()'::jsonpath;
+               ^
+select '$.split_part("~@~", "hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.split_part("~@~", "hi")'::jsonpath;
+               ^
+select '$.split_part("~@~", 2, "extra")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.split_part("~@~", 2, "extra")'::jsonpath;
+               ^
+select '$.lower("hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.lower("hi")'::jsonpath;
+               ^
+select '$.upper("hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.upper("hi")'::jsonpath;
+               ^
+select '$.initcap("hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.initcap("hi")'::jsonpath;
+               ^
+select '$.ltrim(42)'::jsonpath;
+ERROR:  syntax error at or near "42" of jsonpath input
+LINE 1: select '$.ltrim(42)'::jsonpath;
+               ^
+select '$.ltrim("x", "y")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.ltrim("x", "y")'::jsonpath;
+               ^
+select '$.rtrim(42)'::jsonpath;
+ERROR:  syntax error at or near "42" of jsonpath input
+LINE 1: select '$.rtrim(42)'::jsonpath;
+               ^
+select '$.rtrim("x", "y")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.rtrim("x", "y")'::jsonpath;
+               ^
+select '$.trim(42)'::jsonpath;
+ERROR:  syntax error at or near "(" of jsonpath input
+LINE 1: select '$.trim(42)'::jsonpath;
+               ^
+select '$.trim("x", "y")'::jsonpath;
+ERROR:  syntax error at or near "(" of jsonpath input
+LINE 1: select '$.trim("x", "y")'::jsonpath;
+               ^
 select '$.time()'::jsonpath;
  jsonpath 
 ----------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a5269..8169719343e 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -623,6 +623,115 @@ select jsonb_path_query('"2023-08-15 12:34:56 +5:30"', '$.timestamp_tz().string(
 select jsonb_path_query('"2023-08-15 12:34:56"', '$.timestamp().string()');
 rollback;
 
+-- test .ltrim()
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+select jsonb_path_query('"   hello   "', '$.ltrim()');
+select jsonb_path_query('"zzzytest"', '$.ltrim("xyz")');
+select jsonb_path_query('null', '$.ltrim()');
+select jsonb_path_query('null', '$.ltrim()', silent => true);
+select jsonb_path_query('[]', '$.ltrim()');
+select jsonb_path_query('[]', 'strict $.ltrim()');
+select jsonb_path_query('{}', '$.ltrim()');
+select jsonb_path_query('[]', 'strict $.ltrim()', silent => true);
+select jsonb_path_query('{}', '$.ltrim()', silent => true);
+select jsonb_path_query('1.23', '$.ltrim()');
+select jsonb_path_query('"1.23"', '$.ltrim()');
+select jsonb_path_query('"1.23aaa"', '$.ltrim()');
+select jsonb_path_query('1234', '$.ltrim()');
+select jsonb_path_query('true', '$.ltrim()');
+select jsonb_path_query('1234', '$.ltrim().type()');
+select jsonb_path_query('[2, true]', '$.ltrim()');
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim()');
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim().type()');
+
+-- test .rtrim()
+select jsonb_path_query('"   hello   "', '$.rtrim(" ")');
+select jsonb_path_query('"testxxzx"', '$.rtrim("xyz")');
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+
+-- test .btrim()
+select jsonb_path_query('"   hello   "', '$.btrim(" ")');
+select jsonb_path_query('"xyxtrimyyx"', '$.btrim("xyz")');
+select jsonb_path_query('"   hello   "', '$.btrim()');
+select jsonb_path_query('"   hello   "', '$.btrim()');
+
+-- test .lower()
+select jsonb_path_query('null', '$.lower()');
+select jsonb_path_query('null', '$.lower()', silent => true);
+select jsonb_path_query('[]', '$.lower()');
+select jsonb_path_query('[]', 'strict $.lower()');
+select jsonb_path_query('{}', '$.lower()');
+select jsonb_path_query('[]', 'strict $.lower()', silent => true);
+select jsonb_path_query('{}', '$.lower()', silent => true);
+select jsonb_path_query('1.23', '$.lower()');
+select jsonb_path_query('"1.23"', '$.lower()');
+select jsonb_path_query('"1.23aaa"', '$.lower()');
+select jsonb_path_query('1234', '$.lower()');
+select jsonb_path_query('true', '$.lower()');
+select jsonb_path_query('1234', '$.lower().type()');
+select jsonb_path_query('[2, true]', '$.lower()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower().type()');
+
+-- test .upper()
+select jsonb_path_query('null', '$.upper()');
+select jsonb_path_query('null', '$.upper()', silent => true);
+select jsonb_path_query('[]', '$.upper()');
+select jsonb_path_query('[]', 'strict $.upper()');
+select jsonb_path_query('{}', '$.upper()');
+select jsonb_path_query('[]', 'strict $.upper()', silent => true);
+select jsonb_path_query('{}', '$.upper()', silent => true);
+select jsonb_path_query('1.23', '$.upper()');
+select jsonb_path_query('"1.23"', '$.upper()');
+select jsonb_path_query('"1.23aaa"', '$.upper()');
+select jsonb_path_query('1234', '$.upper()');
+select jsonb_path_query('true', '$.upper()');
+select jsonb_path_query('1234', '$.upper().type()');
+select jsonb_path_query('[2, true]', '$.upper()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper().type()');
+
+-- test .initcap()
+select jsonb_path_query('null', '$.initcap()');
+select jsonb_path_query('null', '$.initcap()', silent => true);
+select jsonb_path_query('[]', '$.initcap()');
+select jsonb_path_query('[]', 'strict $.initcap()');
+select jsonb_path_query('{}', '$.initcap()');
+select jsonb_path_query('[]', 'strict $.initcap()', silent => true);
+select jsonb_path_query('{}', '$.initcap()', silent => true);
+select jsonb_path_query('1.23', '$.initcap()');
+select jsonb_path_query('"1.23"', '$.initcap()');
+select jsonb_path_query('"1.23aaa"', '$.initcap()');
+select jsonb_path_query('1234', '$.initcap()');
+select jsonb_path_query('true', '$.initcap()');
+select jsonb_path_query('1234', '$.initcap().type()');
+select jsonb_path_query('[2, true]', '$.initcap()');
+select jsonb_path_query('["maybe yes", "probably no"]', '$.initcap()');
+
+-- Test .replace()
+select jsonb_path_query('null', '$.replace("x", "bye")');
+select jsonb_path_query('null', '$.replace("x", "bye")', silent => true);
+select jsonb_path_query('["x", "y", "z"]', '$.replace("x", "bye")');
+select jsonb_path_query('{}', '$.replace("x", "bye")');
+select jsonb_path_query('[]', 'strict $.replace("x", "bye")', silent => true);
+select jsonb_path_query('{}', '$.replace("x", "bye")', silent => true);
+select jsonb_path_query('1.23', '$.replace("x", "bye")');
+select jsonb_path_query('"hello world"', '$.replace("hello","bye")');
+select jsonb_path_query('"hello world"', '$.replace("hello","bye") starts with "bye"');
+
+-- Test .split_part()
+select jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)');
+select jsonb_path_query('"abc,def,ghi,jkl"', '$.split_part(",", -2)');
+
+-- Test string methods play nicely together
+select jsonb_path_query('"hello world"', '$.replace("hello","bye").upper()');
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye")');
+select jsonb_path_query('"hElLo WorlD"', '$.upper().lower().upper().replace("HELLO", "BYE")');
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye") starts with "bye"');
+select jsonb_path_query('"   hElLo WorlD "', '$.btrim().lower().upper().lower().replace("hello","bye") starts with "bye"');
+
 -- Test .time()
 select jsonb_path_query('null', '$.time()');
 select jsonb_path_query('true', '$.time()');
diff --git a/src/test/regress/sql/jsonpath.sql b/src/test/regress/sql/jsonpath.sql
index 61a5270d4e8..7dd2e57e7a6 100644
--- a/src/test/regress/sql/jsonpath.sql
+++ b/src/test/regress/sql/jsonpath.sql
@@ -78,6 +78,37 @@ select '$.boolean()'::jsonpath;
 select '$.date()'::jsonpath;
 select '$.decimal(4,2)'::jsonpath;
 select '$.string()'::jsonpath;
+select '$.replace("hello","bye")'::jsonpath;
+select '$.lower()'::jsonpath;
+select '$.upper()'::jsonpath;
+select '$.lower().upper().lower().replace("hello","bye")'::jsonpath;
+select '$.ltrim()'::jsonpath;
+select '$.ltrim("xyz")'::jsonpath;
+select '$.rtrim()'::jsonpath;
+select '$.rtrim("xyz")'::jsonpath;
+select '$.btrim()'::jsonpath;
+select '$.btrim("xyz")'::jsonpath;
+select '$.initcap()'::jsonpath;
+select '$.split_part("~@~", 2)'::jsonpath;
+
+-- Parse errors
+select '$.replace("hello")'::jsonpath;
+select '$.replace()'::jsonpath;
+select '$.replace("hello","bye","extra")'::jsonpath;
+select '$.split_part("~@~")'::jsonpath;
+select '$.split_part()'::jsonpath;
+select '$.split_part("~@~", "hi")'::jsonpath;
+select '$.split_part("~@~", 2, "extra")'::jsonpath;
+select '$.lower("hi")'::jsonpath;
+select '$.upper("hi")'::jsonpath;
+select '$.initcap("hi")'::jsonpath;
+select '$.ltrim(42)'::jsonpath;
+select '$.ltrim("x", "y")'::jsonpath;
+select '$.rtrim(42)'::jsonpath;
+select '$.rtrim("x", "y")'::jsonpath;
+select '$.trim(42)'::jsonpath;
+select '$.trim("x", "y")'::jsonpath;
+
 select '$.time()'::jsonpath;
 select '$.time(6)'::jsonpath;
 select '$.time_tz()'::jsonpath;
-- 
2.49.0

From b63773f20c615a79b84522cfcb1b68d4bdfdc7a9 Mon Sep 17 00:00:00 2001
From: "David E. Wheeler" <david@justatheory.com>
Date: Mon, 2 Jun 2025 17:14:10 -0400
Subject: [PATCH v11 1/2] Rename jsonpath method arg tokens

Rename the `csv_` tokens to `int_`, because they represent signed or
unsigned integers, as follows:

*   `csv_elem` => `int_elem`
*   `csv_list` => `int_list`
*   `opt_csv_list` => `opt_int_list`

Rename the `datetime_precision` tokens to `uint_arg`, as they represent
unsigned integers and will be useful for other methods in the future, as
follows:

*   `datetime_precision` => `uint_elem`
*   `opt_datetime_precision` => `opt_uint_arg`

Rename the `datetime_template` tokens to `str_arg`, as they represent
strings and will be useful for other methods in the future, as follows:

*   `datetime_template` => `str_elem`
*   `opt_datetime_template` => `opt_str_arg`
---
 src/backend/utils/adt/jsonpath_gram.y | 42 +++++++++++++--------------
 1 file changed, 21 insertions(+), 21 deletions(-)

diff --git a/src/backend/utils/adt/jsonpath_gram.y b/src/backend/utils/adt/jsonpath_gram.y
index 499745a8fef..0b16cec18c4 100644
--- a/src/backend/utils/adt/jsonpath_gram.y
+++ b/src/backend/utils/adt/jsonpath_gram.y
@@ -92,10 +92,10 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 %type	<value>		scalar_value path_primary expr array_accessor
 					any_path accessor_op key predicate delimited_predicate
 					index_elem starts_with_initial expr_or_predicate
-					datetime_template opt_datetime_template csv_elem
-					datetime_precision opt_datetime_precision
+					str_elem opt_str_arg int_elem
+					uint_elem opt_uint_arg
 
-%type	<elems>		accessor_expr csv_list opt_csv_list
+%type	<elems>		accessor_expr int_list opt_int_list
 
 %type	<indexs>	index_list
 
@@ -254,7 +254,7 @@ accessor_op:
 	| '.' any_path					{ $$ = $2; }
 	| '.' method '(' ')'			{ $$ = makeItemType($2); }
 	| '?' '(' predicate ')'			{ $$ = makeItemUnary(jpiFilter, $3); }
-	| '.' DECIMAL_P '(' opt_csv_list ')'
+	| '.' DECIMAL_P '(' opt_int_list ')'
 		{
 			if (list_length($4) == 0)
 				$$ = makeItemBinary(jpiDecimal, NULL, NULL);
@@ -268,19 +268,19 @@ accessor_op:
 						 errmsg("invalid input syntax for type %s", "jsonpath"),
 						 errdetail(".decimal() can only have an optional precision[,scale].")));
 		}
-	| '.' DATETIME_P '(' opt_datetime_template ')'
+	| '.' DATETIME_P '(' opt_str_arg ')'
 		{ $$ = makeItemUnary(jpiDatetime, $4); }
-	| '.' TIME_P '(' opt_datetime_precision ')'
+	| '.' TIME_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTime, $4); }
-	| '.' TIME_TZ_P '(' opt_datetime_precision ')'
+	| '.' TIME_TZ_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimeTz, $4); }
-	| '.' TIMESTAMP_P '(' opt_datetime_precision ')'
+	| '.' TIMESTAMP_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimestamp, $4); }
-	| '.' TIMESTAMP_TZ_P '(' opt_datetime_precision ')'
+	| '.' TIMESTAMP_TZ_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimestampTz, $4); }
 	;
 
-csv_elem:
+int_elem:
 	INT_P
 		{ $$ = makeItemNumeric(&$1); }
 	| '+' INT_P %prec UMINUS
@@ -289,31 +289,31 @@ csv_elem:
 		{ $$ = makeItemUnary(jpiMinus, makeItemNumeric(&$2)); }
 	;
 
-csv_list:
-	csv_elem						{ $$ = list_make1($1); }
-	| csv_list ',' csv_elem			{ $$ = lappend($1, $3); }
+int_list:
+	int_elem						{ $$ = list_make1($1); }
+	| int_list ',' int_elem			{ $$ = lappend($1, $3); }
 	;
 
-opt_csv_list:
-	csv_list						{ $$ = $1; }
+opt_int_list:
+	int_list						{ $$ = $1; }
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
-datetime_precision:
+uint_elem:
 	INT_P							{ $$ = makeItemNumeric(&$1); }
 	;
 
-opt_datetime_precision:
-	datetime_precision				{ $$ = $1; }
+opt_uint_arg:
+	uint_elem						{ $$ = $1; }
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
-datetime_template:
+str_elem:
 	STRING_P						{ $$ = makeItemString(&$1); }
 	;
 
-opt_datetime_template:
-	datetime_template				{ $$ = $1; }
+opt_str_arg:
+	str_elem						{ $$ = $1; }
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
-- 
2.49.0

From b63773f20c615a79b84522cfcb1b68d4bdfdc7a9 Mon Sep 17 00:00:00 2001
From: "David E. Wheeler" <david@justatheory.com>
Date: Mon, 2 Jun 2025 17:14:10 -0400
Subject: [PATCH v12 1/2] Rename jsonpath method arg tokens

Rename the `csv_` tokens to `int_`, because they represent signed or
unsigned integers, as follows:

*   `csv_elem` => `int_elem`
*   `csv_list` => `int_list`
*   `opt_csv_list` => `opt_int_list`

Rename the `datetime_precision` tokens to `uint_arg`, as they represent
unsigned integers and will be useful for other methods in the future, as
follows:

*   `datetime_precision` => `uint_elem`
*   `opt_datetime_precision` => `opt_uint_arg`

Rename the `datetime_template` tokens to `str_arg`, as they represent
strings and will be useful for other methods in the future, as follows:

*   `datetime_template` => `str_elem`
*   `opt_datetime_template` => `opt_str_arg`
---
 src/backend/utils/adt/jsonpath_gram.y | 42 +++++++++++++--------------
 1 file changed, 21 insertions(+), 21 deletions(-)

diff --git a/src/backend/utils/adt/jsonpath_gram.y b/src/backend/utils/adt/jsonpath_gram.y
index 499745a8fef..0b16cec18c4 100644
--- a/src/backend/utils/adt/jsonpath_gram.y
+++ b/src/backend/utils/adt/jsonpath_gram.y
@@ -92,10 +92,10 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 %type	<value>		scalar_value path_primary expr array_accessor
 					any_path accessor_op key predicate delimited_predicate
 					index_elem starts_with_initial expr_or_predicate
-					datetime_template opt_datetime_template csv_elem
-					datetime_precision opt_datetime_precision
+					str_elem opt_str_arg int_elem
+					uint_elem opt_uint_arg
 
-%type	<elems>		accessor_expr csv_list opt_csv_list
+%type	<elems>		accessor_expr int_list opt_int_list
 
 %type	<indexs>	index_list
 
@@ -254,7 +254,7 @@ accessor_op:
 	| '.' any_path					{ $$ = $2; }
 	| '.' method '(' ')'			{ $$ = makeItemType($2); }
 	| '?' '(' predicate ')'			{ $$ = makeItemUnary(jpiFilter, $3); }
-	| '.' DECIMAL_P '(' opt_csv_list ')'
+	| '.' DECIMAL_P '(' opt_int_list ')'
 		{
 			if (list_length($4) == 0)
 				$$ = makeItemBinary(jpiDecimal, NULL, NULL);
@@ -268,19 +268,19 @@ accessor_op:
 						 errmsg("invalid input syntax for type %s", "jsonpath"),
 						 errdetail(".decimal() can only have an optional precision[,scale].")));
 		}
-	| '.' DATETIME_P '(' opt_datetime_template ')'
+	| '.' DATETIME_P '(' opt_str_arg ')'
 		{ $$ = makeItemUnary(jpiDatetime, $4); }
-	| '.' TIME_P '(' opt_datetime_precision ')'
+	| '.' TIME_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTime, $4); }
-	| '.' TIME_TZ_P '(' opt_datetime_precision ')'
+	| '.' TIME_TZ_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimeTz, $4); }
-	| '.' TIMESTAMP_P '(' opt_datetime_precision ')'
+	| '.' TIMESTAMP_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimestamp, $4); }
-	| '.' TIMESTAMP_TZ_P '(' opt_datetime_precision ')'
+	| '.' TIMESTAMP_TZ_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimestampTz, $4); }
 	;
 
-csv_elem:
+int_elem:
 	INT_P
 		{ $$ = makeItemNumeric(&$1); }
 	| '+' INT_P %prec UMINUS
@@ -289,31 +289,31 @@ csv_elem:
 		{ $$ = makeItemUnary(jpiMinus, makeItemNumeric(&$2)); }
 	;
 
-csv_list:
-	csv_elem						{ $$ = list_make1($1); }
-	| csv_list ',' csv_elem			{ $$ = lappend($1, $3); }
+int_list:
+	int_elem						{ $$ = list_make1($1); }
+	| int_list ',' int_elem			{ $$ = lappend($1, $3); }
 	;
 
-opt_csv_list:
-	csv_list						{ $$ = $1; }
+opt_int_list:
+	int_list						{ $$ = $1; }
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
-datetime_precision:
+uint_elem:
 	INT_P							{ $$ = makeItemNumeric(&$1); }
 	;
 
-opt_datetime_precision:
-	datetime_precision				{ $$ = $1; }
+opt_uint_arg:
+	uint_elem						{ $$ = $1; }
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
-datetime_template:
+str_elem:
 	STRING_P						{ $$ = makeItemString(&$1); }
 	;
 
-opt_datetime_template:
-	datetime_template				{ $$ = $1; }
+opt_str_arg:
+	str_elem						{ $$ = $1; }
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
-- 
2.49.0

From 694cf349f3bfa7e6e8c0d99f91cdc4a9a362d8e0 Mon Sep 17 00:00:00 2001
From: Florents Tselai <florents.tselai@gmail.com>
Date: Fri, 11 Jul 2025 14:04:28 -0400
Subject: [PATCH v12 2/2] Add additional jsonpath string methods

Add the following jsonpath methods:

*   l/r/btrim()
*   lower(), upper()
*   initcap()
*   replace()
*   split_part()

Each simply dispatches to the standard string processing functions.
These depend on the locale, but since it's set at `initdb`, they can be
considered immutable and therefore allowed in any jsonpath expression.
---
 doc/src/sgml/func.sgml                       | 140 +++++++
 src/backend/utils/adt/jsonpath.c             | 117 +++++-
 src/backend/utils/adt/jsonpath_exec.c        | 207 ++++++++++
 src/backend/utils/adt/jsonpath_gram.y        |  28 +-
 src/backend/utils/adt/jsonpath_scan.l        |   8 +
 src/include/utils/jsonpath.h                 |   8 +
 src/test/regress/expected/jsonb_jsonpath.out | 399 +++++++++++++++++++
 src/test/regress/expected/jsonpath.out       | 137 +++++++
 src/test/regress/sql/jsonb_jsonpath.sql      | 109 +++++
 src/test/regress/sql/jsonpath.sql            |  31 ++
 10 files changed, 1179 insertions(+), 5 deletions(-)

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index c28aa71f570..23710921869 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -18637,6 +18637,146 @@ ERROR:  jsonpath member accessor can only be applied to an object
         <returnvalue>[{"id": 0, "key": "x", "value": "20"}, {"id": 0, "key": "y", "value": 32}]</returnvalue>
        </para></entry>
       </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>lower()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String converted to all lower case according to the rules of the database's locale.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"TOM"', '$.lower()')</literal>
+        <returnvalue>"tom"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>upper()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String converted to all upper case according to the rules of the database's locale.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"tom"', '$.upper()')</literal>
+        <returnvalue>"TOM"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>initcap()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the first letter of each word converted to upper case
+        according to the rules of the database's locale. Words are sequences
+        of alphanumeric characters separated by non-alphanumeric characters.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"hi THOMAS"', '$.initcap()')</literal>
+        <returnvalue>"Hi Thomas"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>replace(<replaceable>from</replaceable>, <replaceable>to</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with all occurrences of substring from replaced with substring to.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"abcdefabcdef"', '$.replace("cd", "XX")')</literal>
+        <returnvalue>"abXXefabXXef"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>split_part(<replaceable>delimiter</replaceable>, <replaceable>n</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String split at occurrences of <replaceable>delimiter</replaceable>
+        and returns the <replaceable>n</replaceable>'th field (counting from
+        one) or, when <replaceable>n</replaceable> is negative, returns the
+        |<replaceable>n</replaceable>|'th-from-last field.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)')</literal>
+        <returnvalue>"def"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"abc,def,ghi,jkl"', '$.split_part(",", 2)')</literal>
+        <returnvalue>"ghi"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>ltrim(<replaceable>characters</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the longest string containing only spaces or the
+        characters in <replaceable>characters</replaceable> removed from the
+        start of <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal> jsonb_path_query('"  hello"', '$.ltrim()')</literal>
+        <returnvalue>"hello"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"zzzytest"', '$.ltrim("xyz")')</literal>
+        <returnvalue>"test"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>rtrim([ <replaceable>characters</replaceable> ])</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the longest string containing only spaces or the
+        characters in <replaceable>characters</replaceable> removed from the
+        end of <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"hello  "', '$.rtrim()')</literal>
+        <returnvalue>"hello"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"testxxzx"', '$.rtrim("xyz")')</literal>
+        <returnvalue>"test"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>btrim([ <replaceable>characters</replaceable> ])</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the longest string containing only spaces or the
+        characters in <replaceable>characters</replaceable> removed from the
+        start and end of <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"  hello  "', '$.btrim()')</literal>
+        <returnvalue>"hello"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"xyxtrimyyx"', '$.btrim("xyz")')</literal>
+        <returnvalue>"trim"</returnvalue>
+       </para></entry>
+      </row>
+
      </tbody>
     </tgroup>
    </table>
diff --git a/src/backend/utils/adt/jsonpath.c b/src/backend/utils/adt/jsonpath.c
index 762f7e8a09d..f3f2119a4a8 100644
--- a/src/backend/utils/adt/jsonpath.c
+++ b/src/backend/utils/adt/jsonpath.c
@@ -298,6 +298,8 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 		case jpiMod:
 		case jpiStartsWith:
 		case jpiDecimal:
+		case jpiStrReplace:
+		case jpiStrSplitPart:
 			{
 				/*
 				 * First, reserve place for left/right arg's positions, then
@@ -362,6 +364,9 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 		case jpiTimeTz:
 		case jpiTimestamp:
 		case jpiTimestampTz:
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
 			{
 				int32		arg = reserveSpaceForItemPointer(buf);
 
@@ -457,6 +462,9 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 		case jpiInteger:
 		case jpiNumber:
 		case jpiStringFunc:
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrInitcap:
 			break;
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", item->type);
@@ -831,6 +839,60 @@ printJsonPathItem(StringInfo buf, JsonPathItem *v, bool inKey,
 			}
 			appendStringInfoChar(buf, ')');
 			break;
+		case jpiStrReplace:
+			appendStringInfoString(buf, ".replace(");
+			jspGetLeftArg(v, &elem);
+			printJsonPathItem(buf, &elem, false, false);
+			appendStringInfoChar(buf, ',');
+			jspGetRightArg(v, &elem);
+			printJsonPathItem(buf, &elem, false, false);
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrSplitPart:
+			appendStringInfoString(buf, ".split_part(");
+			jspGetLeftArg(v, &elem);
+			printJsonPathItem(buf, &elem, false, false);
+			appendStringInfoChar(buf, ',');
+			jspGetRightArg(v, &elem);
+			printJsonPathItem(buf, &elem, false, false);
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrLower:
+			appendStringInfoString(buf, ".lower()");
+			break;
+		case jpiStrUpper:
+			appendStringInfoString(buf, ".upper()");
+			break;
+		case jpiStrInitcap:
+			appendStringInfoString(buf, ".initcap()");
+			break;
+		case jpiStrLtrim:
+			appendStringInfoString(buf, ".ltrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrRtrim:
+			appendStringInfoString(buf, ".rtrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrBtrim:
+			appendStringInfoString(buf, ".btrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", v->type);
 	}
@@ -906,6 +968,12 @@ jspOperationName(JsonPathItemType type)
 			return "number";
 		case jpiStringFunc:
 			return "string";
+		case jpiStrReplace:
+			return "replace";
+		case jpiStrLower:
+			return "lower";
+		case jpiStrUpper:
+			return "upper";
 		case jpiTime:
 			return "time";
 		case jpiTimeTz:
@@ -914,6 +982,16 @@ jspOperationName(JsonPathItemType type)
 			return "timestamp";
 		case jpiTimestampTz:
 			return "timestamp_tz";
+		case jpiStrLtrim:
+			return "ltrim";
+		case jpiStrRtrim:
+			return "rtrim";
+		case jpiStrBtrim:
+			return "btrim";
+		case jpiStrInitcap:
+			return "initcap";
+		case jpiStrSplitPart:
+			return "split_part";
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", type);
 			return NULL;
@@ -1016,6 +1094,9 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 		case jpiInteger:
 		case jpiNumber:
 		case jpiStringFunc:
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrInitcap:
 			break;
 		case jpiString:
 		case jpiKey:
@@ -1041,6 +1122,8 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 		case jpiMod:
 		case jpiStartsWith:
 		case jpiDecimal:
+		case jpiStrReplace:
+		case jpiStrSplitPart:
 			read_int32(v->content.args.left, base, pos);
 			read_int32(v->content.args.right, base, pos);
 			break;
@@ -1055,6 +1138,9 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 		case jpiTimeTz:
 		case jpiTimestamp:
 		case jpiTimestampTz:
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
 			read_int32(v->content.arg, base, pos);
 			break;
 		case jpiIndexArray:
@@ -1090,7 +1176,10 @@ jspGetArg(JsonPathItem *v, JsonPathItem *a)
 		   v->type == jpiTime ||
 		   v->type == jpiTimeTz ||
 		   v->type == jpiTimestamp ||
-		   v->type == jpiTimestampTz);
+		   v->type == jpiTimestampTz ||
+		   v->type == jpiStrLtrim ||
+		   v->type == jpiStrRtrim ||
+		   v->type == jpiStrBtrim);
 
 	jspInitByBuffer(a, v->base, v->content.arg);
 }
@@ -1149,10 +1238,18 @@ jspGetNext(JsonPathItem *v, JsonPathItem *a)
 			   v->type == jpiInteger ||
 			   v->type == jpiNumber ||
 			   v->type == jpiStringFunc ||
+			   v->type == jpiStrReplace ||
+			   v->type == jpiStrLower ||
+			   v->type == jpiStrUpper ||
 			   v->type == jpiTime ||
 			   v->type == jpiTimeTz ||
 			   v->type == jpiTimestamp ||
-			   v->type == jpiTimestampTz);
+			   v->type == jpiTimestampTz ||
+			   v->type == jpiStrLtrim ||
+			   v->type == jpiStrRtrim ||
+			   v->type == jpiStrBtrim ||
+			   v->type == jpiStrInitcap ||
+			   v->type == jpiStrSplitPart);
 
 		if (a)
 			jspInitByBuffer(a, v->base, v->nextPos);
@@ -1179,7 +1276,9 @@ jspGetLeftArg(JsonPathItem *v, JsonPathItem *a)
 		   v->type == jpiDiv ||
 		   v->type == jpiMod ||
 		   v->type == jpiStartsWith ||
-		   v->type == jpiDecimal);
+		   v->type == jpiDecimal ||
+		   v->type == jpiStrReplace ||
+		   v->type == jpiStrSplitPart);
 
 	jspInitByBuffer(a, v->base, v->content.args.left);
 }
@@ -1201,7 +1300,9 @@ jspGetRightArg(JsonPathItem *v, JsonPathItem *a)
 		   v->type == jpiDiv ||
 		   v->type == jpiMod ||
 		   v->type == jpiStartsWith ||
-		   v->type == jpiDecimal);
+		   v->type == jpiDecimal ||
+		   v->type == jpiStrReplace ||
+		   v->type == jpiStrSplitPart);
 
 	jspInitByBuffer(a, v->base, v->content.args.right);
 }
@@ -1501,6 +1602,14 @@ jspIsMutableWalker(JsonPathItem *jpi, struct JsonPathMutableContext *cxt)
 			case jpiInteger:
 			case jpiNumber:
 			case jpiStringFunc:
+			case jpiStrReplace:
+			case jpiStrLower:
+			case jpiStrUpper:
+			case jpiStrLtrim:
+			case jpiStrRtrim:
+			case jpiStrBtrim:
+			case jpiStrInitcap:
+			case jpiStrSplitPart:
 				status = jpdsNonDateTime;
 				break;
 
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index dbab24737ef..98418bee9b7 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -301,6 +301,8 @@ static JsonPathExecResult executeNumericItemMethod(JsonPathExecContext *cxt,
 												   JsonValueList *found);
 static JsonPathExecResult executeDateTimeMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
 												JsonbValue *jb, JsonValueList *found);
+static JsonPathExecResult executeStringInternalMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
+													  JsonbValue *jb, JsonValueList *found);
 static JsonPathExecResult executeKeyValueMethod(JsonPathExecContext *cxt,
 												JsonPathItem *jsp, JsonbValue *jb, JsonValueList *found);
 static JsonPathExecResult appendBoolResult(JsonPathExecContext *cxt,
@@ -1659,6 +1661,23 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
 			}
 			break;
 
+		case jpiStrLtrim:
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrReplace:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
+		case jpiStrInitcap:
+		case jpiStrSplitPart:
+			{
+				if (unwrap && JsonbType(jb) == jbvArray)
+					return executeItemUnwrapTargetArray(cxt, jsp, jb, found, false);
+
+				return executeStringInternalMethod(cxt, jsp, jb, found);
+			}
+			break;
+
+
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", jsp->type);
 	}
@@ -2792,6 +2811,194 @@ executeDateTimeMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
 	return executeNextItem(cxt, jsp, &elem, jb, found, hasNext);
 }
 
+/*
+ * Implementation of .upper(), lower() et. al. methods,
+ * that forward their actual implementation to internal functions.
+ */
+static JsonPathExecResult
+executeStringInternalMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
+							JsonbValue *jb, JsonValueList *found)
+{
+	JsonbValue	jbvbuf;
+	bool		hasNext;
+	JsonPathExecResult res = jperNotFound;
+	JsonPathItem elem;
+	Datum		str;			/* Datum representation for the current string
+								 * value. The first argument to internal
+								 * functions */
+	char	   *tmp = NULL;
+	char	   *resStr = NULL;
+
+	Assert(jsp->type == jpiStrLower ||
+		   jsp->type == jpiStrUpper ||
+		   jsp->type == jpiStrReplace ||
+		   jsp->type == jpiStrLtrim ||
+		   jsp->type == jpiStrRtrim ||
+		   jsp->type == jpiStrBtrim ||
+		   jsp->type == jpiStrInitcap ||
+		   jsp->type == jpiStrSplitPart);
+
+	if (!(jb = getScalar(jb, jbvString)))
+		RETURN_ERROR(ereport(ERROR,
+							 (errcode(ERRCODE_INVALID_ARGUMENT_FOR_SQL_JSON_DATETIME_FUNCTION),
+							  errmsg("jsonpath item method .%s() can only be applied to a string",
+									 jspOperationName(jsp->type)))));
+
+	tmp = pnstrdup(jb->val.string.val, jb->val.string.len);
+	str = CStringGetTextDatum(tmp);
+
+	/* Internal string functions that accept no arguments */
+	switch (jsp->type)
+	{
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
+			{
+				char	   *characters_str;
+				int			characters_len;
+				PGFunction	func = NULL;
+
+				if (jsp->content.arg)
+				{
+					switch (jsp->type)
+					{
+						case jpiStrLtrim:
+							func = ltrim;
+							break;
+						case jpiStrRtrim:
+							func = rtrim;
+							break;
+						case jpiStrBtrim:
+							func = btrim;
+							break;
+						default:;
+					}
+					jspGetArg(jsp, &elem);
+					if (elem.type != jpiString)
+						elog(ERROR, "invalid jsonpath item type for .%s() argument", jspOperationName(jsp->type));
+
+					characters_str = jspGetString(&elem, &characters_len);
+					resStr = TextDatumGetCString(DirectFunctionCall2Coll(func,
+																		 DEFAULT_COLLATION_OID, str,
+																		 CStringGetTextDatum(characters_str)));
+					break;
+				}
+
+				switch (jsp->type)
+				{
+					case jpiStrLtrim:
+						func = ltrim1;
+						break;
+					case jpiStrRtrim:
+						func = rtrim1;
+						break;
+					case jpiStrBtrim:
+						func = btrim1;
+						break;
+					default:;
+				}
+				resStr = TextDatumGetCString(DirectFunctionCall1Coll(func,
+																	 DEFAULT_COLLATION_OID, str));
+				break;
+			}
+
+		case jpiStrLower:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(lower, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiStrUpper:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(upper, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiStrInitcap:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(initcap, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiStrReplace:
+			{
+				char	   *from_str,
+						   *to_str;
+				int			from_len,
+							to_len;
+
+				jspGetLeftArg(jsp, &elem);
+				if (elem.type != jpiString)
+					elog(ERROR, "invalid jsonpath item type for .replace() from");
+
+				from_str = jspGetString(&elem, &from_len);
+
+				jspGetRightArg(jsp, &elem);
+				if (elem.type != jpiString)
+					elog(ERROR, "invalid jsonpath item type for .replace() to");
+
+				to_str = jspGetString(&elem, &to_len);
+
+				resStr = TextDatumGetCString(DirectFunctionCall3Coll(replace_text,
+																	 C_COLLATION_OID,
+																	 CStringGetTextDatum(tmp),
+																	 CStringGetTextDatum(from_str),
+																	 CStringGetTextDatum(to_str)));
+				break;
+			}
+		case jpiStrSplitPart:
+			{
+				char	   *from_str;
+				Numeric		n;
+				int			from_len;
+
+				jspGetLeftArg(jsp, &elem);
+				if (elem.type != jpiString)
+					elog(ERROR, "invalid jsonpath item type for .split_part()");
+
+				from_str = jspGetString(&elem, &from_len);
+
+				jspGetRightArg(jsp, &elem);
+				if (elem.type != jpiNumeric)
+					elog(ERROR, "invalid jsonpath item type for .split_part()");
+
+				n = jspGetNumeric(&elem);
+
+				resStr = TextDatumGetCString(DirectFunctionCall3Coll(split_part,
+																	 C_COLLATION_OID,
+																	 CStringGetTextDatum(tmp),
+																	 CStringGetTextDatum(from_str),
+																	 DirectFunctionCall1(numeric_int4, NumericGetDatum(n))));
+				break;
+			}
+		default:
+			elog(ERROR, "unsupported jsonpath item type: %d", jsp->type);
+	}
+
+	if (resStr)
+		res = jperOk;
+
+	hasNext = jspGetNext(jsp, &elem);
+
+	if (!hasNext && !found)
+		return res;
+
+	jb = hasNext ? &jbvbuf : palloc(sizeof(*jb));
+
+	/* Create the appropriate jb value to return */
+	switch (jsp->type)
+	{
+			/* Cases for functions that return text */
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrReplace:
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
+		case jpiStrInitcap:
+		case jpiStrSplitPart:
+			jb->type = jbvString;
+			jb->val.string.val = resStr;
+			jb->val.string.len = strlen(jb->val.string.val);
+		default:
+			;
+			/* cant' happen */
+	}
+
+	return executeNextItem(cxt, jsp, &elem, jb, found, hasNext);
+}
+
 /*
  * Implementation of .keyvalue() method.
  *
diff --git a/src/backend/utils/adt/jsonpath_gram.y b/src/backend/utils/adt/jsonpath_gram.y
index 0b16cec18c4..53bf779e152 100644
--- a/src/backend/utils/adt/jsonpath_gram.y
+++ b/src/backend/utils/adt/jsonpath_gram.y
@@ -86,6 +86,8 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 %token	<str>		DATETIME_P
 %token	<str>		BIGINT_P BOOLEAN_P DATE_P DECIMAL_P INTEGER_P NUMBER_P
 %token	<str>		STRINGFUNC_P TIME_P TIME_TZ_P TIMESTAMP_P TIMESTAMP_TZ_P
+%token	<str>		STR_REPLACE_P STR_LOWER_P STR_UPPER_P STR_LTRIM_P STR_RTRIM_P STR_BTRIM_P
+					STR_INITCAP_P STR_SPLIT_PART_P
 
 %type	<result>	result
 
@@ -95,7 +97,7 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 					str_elem opt_str_arg int_elem
 					uint_elem opt_uint_arg
 
-%type	<elems>		accessor_expr int_list opt_int_list
+%type	<elems>		accessor_expr int_list opt_int_list str_int_args str_str_args
 
 %type	<indexs>	index_list
 
@@ -278,6 +280,16 @@ accessor_op:
 		{ $$ = makeItemUnary(jpiTimestamp, $4); }
 	| '.' TIMESTAMP_TZ_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimestampTz, $4); }
+	| '.' STR_REPLACE_P '(' str_str_args ')'
+		{ $$ = makeItemBinary(jpiStrReplace, linitial($4), lsecond($4)); }
+	| '.' STR_SPLIT_PART_P '(' str_int_args ')'
+		{ $$ = makeItemBinary(jpiStrSplitPart, linitial($4), lsecond($4)); }
+	| '.' STR_LTRIM_P '(' opt_str_arg ')'
+		{ $$ = makeItemUnary(jpiStrLtrim, $4); }
+	| '.' STR_RTRIM_P '(' opt_str_arg ')'
+		{ $$ = makeItemUnary(jpiStrRtrim, $4); }
+	| '.' STR_BTRIM_P '(' opt_str_arg ')'
+		{ $$ = makeItemUnary(jpiStrBtrim, $4); }
 	;
 
 int_elem:
@@ -317,6 +329,14 @@ opt_str_arg:
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
+str_int_args:
+	str_elem ',' int_elem			{ $$ = list_make2($1, $3); }
+	;
+
+str_str_args:
+	str_elem ',' str_elem 			{ $$ = list_make2($1, $3); }
+	;
+
 key:
 	key_name						{ $$ = makeItemKey(&$1); }
 	;
@@ -357,6 +377,9 @@ key_name:
 	| TIME_TZ_P
 	| TIMESTAMP_P
 	| TIMESTAMP_TZ_P
+	| STR_LTRIM_P
+	| STR_RTRIM_P
+	| STR_BTRIM_P
 	;
 
 method:
@@ -373,6 +396,9 @@ method:
 	| INTEGER_P						{ $$ = jpiInteger; }
 	| NUMBER_P						{ $$ = jpiNumber; }
 	| STRINGFUNC_P					{ $$ = jpiStringFunc; }
+	| STR_LOWER_P					{ $$ = jpiStrLower; }
+	| STR_UPPER_P					{ $$ = jpiStrUpper; }
+	| STR_INITCAP_P					{ $$ = jpiStrInitcap; }
 	;
 %%
 
diff --git a/src/backend/utils/adt/jsonpath_scan.l b/src/backend/utils/adt/jsonpath_scan.l
index c7aab83eeb4..69c61f98500 100644
--- a/src/backend/utils/adt/jsonpath_scan.l
+++ b/src/backend/utils/adt/jsonpath_scan.l
@@ -413,8 +413,13 @@ static const JsonPathKeyword keywords[] = {
 	{4, true, TRUE_P, "true"},
 	{4, false, TYPE_P, "type"},
 	{4, false, WITH_P, "with"},
+	{5, false, STR_BTRIM_P, "btrim"},
 	{5, true, FALSE_P, "false"},
 	{5, false, FLOOR_P, "floor"},
+	{5, false, STR_LOWER_P, "lower"},
+	{5, false, STR_LTRIM_P, "ltrim"},
+	{5, false, STR_RTRIM_P, "rtrim"},
+	{5, false, STR_UPPER_P, "upper"},
 	{6, false, BIGINT_P, "bigint"},
 	{6, false, DOUBLE_P, "double"},
 	{6, false, EXISTS_P, "exists"},
@@ -425,13 +430,16 @@ static const JsonPathKeyword keywords[] = {
 	{7, false, BOOLEAN_P, "boolean"},
 	{7, false, CEILING_P, "ceiling"},
 	{7, false, DECIMAL_P, "decimal"},
+	{7, false, STR_INITCAP_P, "initcap"},
 	{7, false, INTEGER_P, "integer"},
+	{7, false, STR_REPLACE_P, "replace"},
 	{7, false, TIME_TZ_P, "time_tz"},
 	{7, false, UNKNOWN_P, "unknown"},
 	{8, false, DATETIME_P, "datetime"},
 	{8, false, KEYVALUE_P, "keyvalue"},
 	{9, false, TIMESTAMP_P, "timestamp"},
 	{10, false, LIKE_REGEX_P, "like_regex"},
+	{10,false, STR_SPLIT_PART_P, "split_part"},
 	{12, false, TIMESTAMP_TZ_P, "timestamp_tz"},
 };
 
diff --git a/src/include/utils/jsonpath.h b/src/include/utils/jsonpath.h
index 23a76d233e9..2d0c53f7b06 100644
--- a/src/include/utils/jsonpath.h
+++ b/src/include/utils/jsonpath.h
@@ -115,6 +115,14 @@ typedef enum JsonPathItemType
 	jpiTimeTz,					/* .time_tz() item method */
 	jpiTimestamp,				/* .timestamp() item method */
 	jpiTimestampTz,				/* .timestamp_tz() item method */
+	jpiStrReplace,				/* .replace() item method */
+	jpiStrLower,				/* .lower() item method */
+	jpiStrUpper,				/* .upper() item method */
+	jpiStrLtrim,				/* .ltrim() item method */
+	jpiStrRtrim,				/* .rtrim() item method */
+	jpiStrBtrim,				/* .btrim() item method */
+	jpiStrInitcap,				/* .initcap() item method */
+	jpiStrSplitPart,			/* .split_part() item method */
 } JsonPathItemType;
 
 /* XQuery regex mode flags for LIKE_REGEX predicate */
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e91a29..cea539717f9 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -2723,6 +2723,405 @@ select jsonb_path_query('"2023-08-15 12:34:56"', '$.timestamp().string()');
 (1 row)
 
 rollback;
+-- test .ltrim()
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"zzzytest"', '$.ltrim("xyz")');
+ jsonb_path_query 
+------------------
+ "test"
+(1 row)
+
+select jsonb_path_query('null', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('null', '$.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.ltrim()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('{}', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('true', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('1234', '$.ltrim().type()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim()');
+  jsonb_path_query_array  
+--------------------------
+ ["maybe  ", "yes", "no"]
+(1 row)
+
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .rtrim()
+select jsonb_path_query('"   hello   "', '$.rtrim(" ")');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+select jsonb_path_query('"testxxzx"', '$.rtrim("xyz")');
+ jsonb_path_query 
+------------------
+ "test"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+-- test .btrim()
+select jsonb_path_query('"   hello   "', '$.btrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+select jsonb_path_query('"xyxtrimyyx"', '$.btrim("xyz")');
+ jsonb_path_query 
+------------------
+ "trim"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.btrim()');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.btrim()');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+-- test .lower()
+select jsonb_path_query('null', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('null', '$.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.lower()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('{}', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.lower()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.lower()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('true', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('1234', '$.lower().type()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower()');
+ jsonb_path_query_array 
+------------------------
+ ["maybe", "yes", "no"]
+(1 row)
+
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .upper()
+select jsonb_path_query('null', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('null', '$.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.upper()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('{}', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.upper()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.upper()');
+ jsonb_path_query 
+------------------
+ "1.23AAA"
+(1 row)
+
+select jsonb_path_query('1234', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('true', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('1234', '$.upper().type()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper()');
+ jsonb_path_query_array 
+------------------------
+ ["MAYBE", "YES", "NO"]
+(1 row)
+
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .initcap()
+select jsonb_path_query('null', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('null', '$.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.initcap()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('{}', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('true', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('1234', '$.initcap().type()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('["maybe yes", "probably no"]', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "Maybe Yes"
+ "Probably No"
+(2 rows)
+
+-- Test .replace()
+select jsonb_path_query('null', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('null', '$.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('["x", "y", "z"]', '$.replace("x", "bye")');
+ jsonb_path_query 
+------------------
+ "bye"
+ "y"
+ "z"
+(3 rows)
+
+select jsonb_path_query('{}', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('"hello world"', '$.replace("hello","bye")');
+ jsonb_path_query 
+------------------
+ "bye world"
+(1 row)
+
+select jsonb_path_query('"hello world"', '$.replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
+-- Test .split_part()
+select jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)');
+ jsonb_path_query 
+------------------
+ "def"
+(1 row)
+
+select jsonb_path_query('"abc,def,ghi,jkl"', '$.split_part(",", -2)');
+ jsonb_path_query 
+------------------
+ "ghi"
+(1 row)
+
+-- Test string methods play nicely together
+select jsonb_path_query('"hello world"', '$.replace("hello","bye").upper()');
+ jsonb_path_query 
+------------------
+ "BYE WORLD"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye")');
+ jsonb_path_query 
+------------------
+ "bye world"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.upper().lower().upper().replace("HELLO", "BYE")');
+ jsonb_path_query 
+------------------
+ "BYE WORLD"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
+select jsonb_path_query('"   hElLo WorlD "', '$.btrim().lower().upper().lower().replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
 -- Test .time()
 select jsonb_path_query('null', '$.time()');
 ERROR:  jsonpath item method .time() can only be applied to a string
diff --git a/src/test/regress/expected/jsonpath.out b/src/test/regress/expected/jsonpath.out
index fd9bd755f52..a13022feabd 100644
--- a/src/test/regress/expected/jsonpath.out
+++ b/src/test/regress/expected/jsonpath.out
@@ -435,6 +435,143 @@ select '$.string()'::jsonpath;
  $.string()
 (1 row)
 
+select '$.replace("hello","bye")'::jsonpath;
+         jsonpath         
+--------------------------
+ $.replace("hello","bye")
+(1 row)
+
+select '$.lower()'::jsonpath;
+ jsonpath  
+-----------
+ $.lower()
+(1 row)
+
+select '$.upper()'::jsonpath;
+ jsonpath  
+-----------
+ $.upper()
+(1 row)
+
+select '$.lower().upper().lower().replace("hello","bye")'::jsonpath;
+                     jsonpath                     
+--------------------------------------------------
+ $.lower().upper().lower().replace("hello","bye")
+(1 row)
+
+select '$.ltrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.ltrim()
+(1 row)
+
+select '$.ltrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.ltrim("xyz")
+(1 row)
+
+select '$.rtrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.rtrim()
+(1 row)
+
+select '$.rtrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.rtrim("xyz")
+(1 row)
+
+select '$.btrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.btrim()
+(1 row)
+
+select '$.btrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.btrim("xyz")
+(1 row)
+
+select '$.initcap()'::jsonpath;
+  jsonpath   
+-------------
+ $.initcap()
+(1 row)
+
+select '$.split_part("~@~", 2)'::jsonpath;
+       jsonpath        
+-----------------------
+ $.split_part("~@~",2)
+(1 row)
+
+-- Parse errors
+select '$.replace("hello")'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.replace("hello")'::jsonpath;
+               ^
+select '$.replace()'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.replace()'::jsonpath;
+               ^
+select '$.replace("hello","bye","extra")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.replace("hello","bye","extra")'::jsonpath;
+               ^
+select '$.split_part("~@~")'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.split_part("~@~")'::jsonpath;
+               ^
+select '$.split_part()'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.split_part()'::jsonpath;
+               ^
+select '$.split_part("~@~", "hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.split_part("~@~", "hi")'::jsonpath;
+               ^
+select '$.split_part("~@~", 2, "extra")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.split_part("~@~", 2, "extra")'::jsonpath;
+               ^
+select '$.lower("hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.lower("hi")'::jsonpath;
+               ^
+select '$.upper("hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.upper("hi")'::jsonpath;
+               ^
+select '$.initcap("hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.initcap("hi")'::jsonpath;
+               ^
+select '$.ltrim(42)'::jsonpath;
+ERROR:  syntax error at or near "42" of jsonpath input
+LINE 1: select '$.ltrim(42)'::jsonpath;
+               ^
+select '$.ltrim("x", "y")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.ltrim("x", "y")'::jsonpath;
+               ^
+select '$.rtrim(42)'::jsonpath;
+ERROR:  syntax error at or near "42" of jsonpath input
+LINE 1: select '$.rtrim(42)'::jsonpath;
+               ^
+select '$.rtrim("x", "y")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.rtrim("x", "y")'::jsonpath;
+               ^
+select '$.trim(42)'::jsonpath;
+ERROR:  syntax error at or near "(" of jsonpath input
+LINE 1: select '$.trim(42)'::jsonpath;
+               ^
+select '$.trim("x", "y")'::jsonpath;
+ERROR:  syntax error at or near "(" of jsonpath input
+LINE 1: select '$.trim("x", "y")'::jsonpath;
+               ^
 select '$.time()'::jsonpath;
  jsonpath 
 ----------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a5269..8169719343e 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -623,6 +623,115 @@ select jsonb_path_query('"2023-08-15 12:34:56 +5:30"', '$.timestamp_tz().string(
 select jsonb_path_query('"2023-08-15 12:34:56"', '$.timestamp().string()');
 rollback;
 
+-- test .ltrim()
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+select jsonb_path_query('"   hello   "', '$.ltrim()');
+select jsonb_path_query('"zzzytest"', '$.ltrim("xyz")');
+select jsonb_path_query('null', '$.ltrim()');
+select jsonb_path_query('null', '$.ltrim()', silent => true);
+select jsonb_path_query('[]', '$.ltrim()');
+select jsonb_path_query('[]', 'strict $.ltrim()');
+select jsonb_path_query('{}', '$.ltrim()');
+select jsonb_path_query('[]', 'strict $.ltrim()', silent => true);
+select jsonb_path_query('{}', '$.ltrim()', silent => true);
+select jsonb_path_query('1.23', '$.ltrim()');
+select jsonb_path_query('"1.23"', '$.ltrim()');
+select jsonb_path_query('"1.23aaa"', '$.ltrim()');
+select jsonb_path_query('1234', '$.ltrim()');
+select jsonb_path_query('true', '$.ltrim()');
+select jsonb_path_query('1234', '$.ltrim().type()');
+select jsonb_path_query('[2, true]', '$.ltrim()');
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim()');
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim().type()');
+
+-- test .rtrim()
+select jsonb_path_query('"   hello   "', '$.rtrim(" ")');
+select jsonb_path_query('"testxxzx"', '$.rtrim("xyz")');
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+
+-- test .btrim()
+select jsonb_path_query('"   hello   "', '$.btrim(" ")');
+select jsonb_path_query('"xyxtrimyyx"', '$.btrim("xyz")');
+select jsonb_path_query('"   hello   "', '$.btrim()');
+select jsonb_path_query('"   hello   "', '$.btrim()');
+
+-- test .lower()
+select jsonb_path_query('null', '$.lower()');
+select jsonb_path_query('null', '$.lower()', silent => true);
+select jsonb_path_query('[]', '$.lower()');
+select jsonb_path_query('[]', 'strict $.lower()');
+select jsonb_path_query('{}', '$.lower()');
+select jsonb_path_query('[]', 'strict $.lower()', silent => true);
+select jsonb_path_query('{}', '$.lower()', silent => true);
+select jsonb_path_query('1.23', '$.lower()');
+select jsonb_path_query('"1.23"', '$.lower()');
+select jsonb_path_query('"1.23aaa"', '$.lower()');
+select jsonb_path_query('1234', '$.lower()');
+select jsonb_path_query('true', '$.lower()');
+select jsonb_path_query('1234', '$.lower().type()');
+select jsonb_path_query('[2, true]', '$.lower()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower().type()');
+
+-- test .upper()
+select jsonb_path_query('null', '$.upper()');
+select jsonb_path_query('null', '$.upper()', silent => true);
+select jsonb_path_query('[]', '$.upper()');
+select jsonb_path_query('[]', 'strict $.upper()');
+select jsonb_path_query('{}', '$.upper()');
+select jsonb_path_query('[]', 'strict $.upper()', silent => true);
+select jsonb_path_query('{}', '$.upper()', silent => true);
+select jsonb_path_query('1.23', '$.upper()');
+select jsonb_path_query('"1.23"', '$.upper()');
+select jsonb_path_query('"1.23aaa"', '$.upper()');
+select jsonb_path_query('1234', '$.upper()');
+select jsonb_path_query('true', '$.upper()');
+select jsonb_path_query('1234', '$.upper().type()');
+select jsonb_path_query('[2, true]', '$.upper()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper().type()');
+
+-- test .initcap()
+select jsonb_path_query('null', '$.initcap()');
+select jsonb_path_query('null', '$.initcap()', silent => true);
+select jsonb_path_query('[]', '$.initcap()');
+select jsonb_path_query('[]', 'strict $.initcap()');
+select jsonb_path_query('{}', '$.initcap()');
+select jsonb_path_query('[]', 'strict $.initcap()', silent => true);
+select jsonb_path_query('{}', '$.initcap()', silent => true);
+select jsonb_path_query('1.23', '$.initcap()');
+select jsonb_path_query('"1.23"', '$.initcap()');
+select jsonb_path_query('"1.23aaa"', '$.initcap()');
+select jsonb_path_query('1234', '$.initcap()');
+select jsonb_path_query('true', '$.initcap()');
+select jsonb_path_query('1234', '$.initcap().type()');
+select jsonb_path_query('[2, true]', '$.initcap()');
+select jsonb_path_query('["maybe yes", "probably no"]', '$.initcap()');
+
+-- Test .replace()
+select jsonb_path_query('null', '$.replace("x", "bye")');
+select jsonb_path_query('null', '$.replace("x", "bye")', silent => true);
+select jsonb_path_query('["x", "y", "z"]', '$.replace("x", "bye")');
+select jsonb_path_query('{}', '$.replace("x", "bye")');
+select jsonb_path_query('[]', 'strict $.replace("x", "bye")', silent => true);
+select jsonb_path_query('{}', '$.replace("x", "bye")', silent => true);
+select jsonb_path_query('1.23', '$.replace("x", "bye")');
+select jsonb_path_query('"hello world"', '$.replace("hello","bye")');
+select jsonb_path_query('"hello world"', '$.replace("hello","bye") starts with "bye"');
+
+-- Test .split_part()
+select jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)');
+select jsonb_path_query('"abc,def,ghi,jkl"', '$.split_part(",", -2)');
+
+-- Test string methods play nicely together
+select jsonb_path_query('"hello world"', '$.replace("hello","bye").upper()');
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye")');
+select jsonb_path_query('"hElLo WorlD"', '$.upper().lower().upper().replace("HELLO", "BYE")');
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye") starts with "bye"');
+select jsonb_path_query('"   hElLo WorlD "', '$.btrim().lower().upper().lower().replace("hello","bye") starts with "bye"');
+
 -- Test .time()
 select jsonb_path_query('null', '$.time()');
 select jsonb_path_query('true', '$.time()');
diff --git a/src/test/regress/sql/jsonpath.sql b/src/test/regress/sql/jsonpath.sql
index 61a5270d4e8..7dd2e57e7a6 100644
--- a/src/test/regress/sql/jsonpath.sql
+++ b/src/test/regress/sql/jsonpath.sql
@@ -78,6 +78,37 @@ select '$.boolean()'::jsonpath;
 select '$.date()'::jsonpath;
 select '$.decimal(4,2)'::jsonpath;
 select '$.string()'::jsonpath;
+select '$.replace("hello","bye")'::jsonpath;
+select '$.lower()'::jsonpath;
+select '$.upper()'::jsonpath;
+select '$.lower().upper().lower().replace("hello","bye")'::jsonpath;
+select '$.ltrim()'::jsonpath;
+select '$.ltrim("xyz")'::jsonpath;
+select '$.rtrim()'::jsonpath;
+select '$.rtrim("xyz")'::jsonpath;
+select '$.btrim()'::jsonpath;
+select '$.btrim("xyz")'::jsonpath;
+select '$.initcap()'::jsonpath;
+select '$.split_part("~@~", 2)'::jsonpath;
+
+-- Parse errors
+select '$.replace("hello")'::jsonpath;
+select '$.replace()'::jsonpath;
+select '$.replace("hello","bye","extra")'::jsonpath;
+select '$.split_part("~@~")'::jsonpath;
+select '$.split_part()'::jsonpath;
+select '$.split_part("~@~", "hi")'::jsonpath;
+select '$.split_part("~@~", 2, "extra")'::jsonpath;
+select '$.lower("hi")'::jsonpath;
+select '$.upper("hi")'::jsonpath;
+select '$.initcap("hi")'::jsonpath;
+select '$.ltrim(42)'::jsonpath;
+select '$.ltrim("x", "y")'::jsonpath;
+select '$.rtrim(42)'::jsonpath;
+select '$.rtrim("x", "y")'::jsonpath;
+select '$.trim(42)'::jsonpath;
+select '$.trim("x", "y")'::jsonpath;
+
 select '$.time()'::jsonpath;
 select '$.time(6)'::jsonpath;
 select '$.time_tz()'::jsonpath;
-- 
2.49.0

From 70c08c3e835eb753c7bd30aed67a9a786eb144e7 Mon Sep 17 00:00:00 2001
From: "David E. Wheeler" <david@justatheory.com>
Date: Mon, 2 Jun 2025 17:14:10 -0400
Subject: [PATCH v13 1/2] Rename jsonpath method arg tokens

Rename the `csv_` tokens to `int_`, because they represent signed or
unsigned integers, as follows:

*   `csv_elem` => `int_elem`
*   `csv_list` => `int_list`
*   `opt_csv_list` => `opt_int_list`

Rename the `datetime_precision` tokens to `uint_arg`, as they represent
unsigned integers and will be useful for other methods in the future, as
follows:

*   `datetime_precision` => `uint_elem`
*   `opt_datetime_precision` => `opt_uint_arg`

Rename the `datetime_template` tokens to `str_arg`, as they represent
strings and will be useful for other methods in the future, as follows:

*   `datetime_template` => `str_elem`
*   `opt_datetime_template` => `opt_str_arg`
---
 src/backend/utils/adt/jsonpath_gram.y | 42 +++++++++++++--------------
 1 file changed, 21 insertions(+), 21 deletions(-)

diff --git a/src/backend/utils/adt/jsonpath_gram.y b/src/backend/utils/adt/jsonpath_gram.y
index 499745a8fef..0b16cec18c4 100644
--- a/src/backend/utils/adt/jsonpath_gram.y
+++ b/src/backend/utils/adt/jsonpath_gram.y
@@ -92,10 +92,10 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 %type	<value>		scalar_value path_primary expr array_accessor
 					any_path accessor_op key predicate delimited_predicate
 					index_elem starts_with_initial expr_or_predicate
-					datetime_template opt_datetime_template csv_elem
-					datetime_precision opt_datetime_precision
+					str_elem opt_str_arg int_elem
+					uint_elem opt_uint_arg
 
-%type	<elems>		accessor_expr csv_list opt_csv_list
+%type	<elems>		accessor_expr int_list opt_int_list
 
 %type	<indexs>	index_list
 
@@ -254,7 +254,7 @@ accessor_op:
 	| '.' any_path					{ $$ = $2; }
 	| '.' method '(' ')'			{ $$ = makeItemType($2); }
 	| '?' '(' predicate ')'			{ $$ = makeItemUnary(jpiFilter, $3); }
-	| '.' DECIMAL_P '(' opt_csv_list ')'
+	| '.' DECIMAL_P '(' opt_int_list ')'
 		{
 			if (list_length($4) == 0)
 				$$ = makeItemBinary(jpiDecimal, NULL, NULL);
@@ -268,19 +268,19 @@ accessor_op:
 						 errmsg("invalid input syntax for type %s", "jsonpath"),
 						 errdetail(".decimal() can only have an optional precision[,scale].")));
 		}
-	| '.' DATETIME_P '(' opt_datetime_template ')'
+	| '.' DATETIME_P '(' opt_str_arg ')'
 		{ $$ = makeItemUnary(jpiDatetime, $4); }
-	| '.' TIME_P '(' opt_datetime_precision ')'
+	| '.' TIME_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTime, $4); }
-	| '.' TIME_TZ_P '(' opt_datetime_precision ')'
+	| '.' TIME_TZ_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimeTz, $4); }
-	| '.' TIMESTAMP_P '(' opt_datetime_precision ')'
+	| '.' TIMESTAMP_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimestamp, $4); }
-	| '.' TIMESTAMP_TZ_P '(' opt_datetime_precision ')'
+	| '.' TIMESTAMP_TZ_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimestampTz, $4); }
 	;
 
-csv_elem:
+int_elem:
 	INT_P
 		{ $$ = makeItemNumeric(&$1); }
 	| '+' INT_P %prec UMINUS
@@ -289,31 +289,31 @@ csv_elem:
 		{ $$ = makeItemUnary(jpiMinus, makeItemNumeric(&$2)); }
 	;
 
-csv_list:
-	csv_elem						{ $$ = list_make1($1); }
-	| csv_list ',' csv_elem			{ $$ = lappend($1, $3); }
+int_list:
+	int_elem						{ $$ = list_make1($1); }
+	| int_list ',' int_elem			{ $$ = lappend($1, $3); }
 	;
 
-opt_csv_list:
-	csv_list						{ $$ = $1; }
+opt_int_list:
+	int_list						{ $$ = $1; }
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
-datetime_precision:
+uint_elem:
 	INT_P							{ $$ = makeItemNumeric(&$1); }
 	;
 
-opt_datetime_precision:
-	datetime_precision				{ $$ = $1; }
+opt_uint_arg:
+	uint_elem						{ $$ = $1; }
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
-datetime_template:
+str_elem:
 	STRING_P						{ $$ = makeItemString(&$1); }
 	;
 
-opt_datetime_template:
-	datetime_template				{ $$ = $1; }
+opt_str_arg:
+	str_elem						{ $$ = $1; }
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
-- 
2.47.3

From 528766497f8ac164b950e049216212daab39c8f2 Mon Sep 17 00:00:00 2001
From: Florents Tselai <florents.tselai@gmail.com>
Date: Fri, 11 Jul 2025 14:04:28 -0400
Subject: [PATCH v13 2/2] Add additional jsonpath string methods

Add the following jsonpath methods:

*   l/r/btrim()
*   lower(), upper()
*   initcap()
*   replace()
*   split_part()

Each simply dispatches to the standard string processing functions.
These depend on the locale, but since it's set at `initdb`, they can be
considered immutable and therefore allowed in any jsonpath expression.
---
 doc/src/sgml/func/func-json.sgml             | 140 +++++++
 src/backend/utils/adt/jsonpath.c             | 117 +++++-
 src/backend/utils/adt/jsonpath_exec.c        | 207 ++++++++++
 src/backend/utils/adt/jsonpath_gram.y        |  28 +-
 src/backend/utils/adt/jsonpath_scan.l        |   8 +
 src/include/utils/jsonpath.h                 |   8 +
 src/test/regress/expected/jsonb_jsonpath.out | 399 +++++++++++++++++++
 src/test/regress/expected/jsonpath.out       | 137 +++++++
 src/test/regress/sql/jsonb_jsonpath.sql      | 109 +++++
 src/test/regress/sql/jsonpath.sql            |  31 ++
 10 files changed, 1179 insertions(+), 5 deletions(-)

diff --git a/doc/src/sgml/func/func-json.sgml b/doc/src/sgml/func/func-json.sgml
index b9316ba0ee5..49031820c4b 100644
--- a/doc/src/sgml/func/func-json.sgml
+++ b/doc/src/sgml/func/func-json.sgml
@@ -2781,6 +2781,146 @@ ERROR:  jsonpath member accessor can only be applied to an object
         <returnvalue>[{"id": 0, "key": "x", "value": "20"}, {"id": 0, "key": "y", "value": 32}]</returnvalue>
        </para></entry>
       </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>lower()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String converted to all lower case according to the rules of the database's locale.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"TOM"', '$.lower()')</literal>
+        <returnvalue>"tom"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>upper()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String converted to all upper case according to the rules of the database's locale.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"tom"', '$.upper()')</literal>
+        <returnvalue>"TOM"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>initcap()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the first letter of each word converted to upper case
+        according to the rules of the database's locale. Words are sequences
+        of alphanumeric characters separated by non-alphanumeric characters.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"hi THOMAS"', '$.initcap()')</literal>
+        <returnvalue>"Hi Thomas"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>replace(<replaceable>from</replaceable>, <replaceable>to</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with all occurrences of substring from replaced with substring to.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"abcdefabcdef"', '$.replace("cd", "XX")')</literal>
+        <returnvalue>"abXXefabXXef"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>split_part(<replaceable>delimiter</replaceable>, <replaceable>n</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String split at occurrences of <replaceable>delimiter</replaceable>
+        and returns the <replaceable>n</replaceable>'th field (counting from
+        one) or, when <replaceable>n</replaceable> is negative, returns the
+        |<replaceable>n</replaceable>|'th-from-last field.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)')</literal>
+        <returnvalue>"def"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"abc,def,ghi,jkl"', '$.split_part(",", 2)')</literal>
+        <returnvalue>"ghi"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>ltrim(<replaceable>characters</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the longest string containing only spaces or the
+        characters in <replaceable>characters</replaceable> removed from the
+        start of <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal> jsonb_path_query('"  hello"', '$.ltrim()')</literal>
+        <returnvalue>"hello"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"zzzytest"', '$.ltrim("xyz")')</literal>
+        <returnvalue>"test"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>rtrim([ <replaceable>characters</replaceable> ])</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the longest string containing only spaces or the
+        characters in <replaceable>characters</replaceable> removed from the
+        end of <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"hello  "', '$.rtrim()')</literal>
+        <returnvalue>"hello"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"testxxzx"', '$.rtrim("xyz")')</literal>
+        <returnvalue>"test"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>btrim([ <replaceable>characters</replaceable> ])</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the longest string containing only spaces or the
+        characters in <replaceable>characters</replaceable> removed from the
+        start and end of <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"  hello  "', '$.btrim()')</literal>
+        <returnvalue>"hello"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"xyxtrimyyx"', '$.btrim("xyz")')</literal>
+        <returnvalue>"trim"</returnvalue>
+       </para></entry>
+      </row>
+
      </tbody>
     </tgroup>
    </table>
diff --git a/src/backend/utils/adt/jsonpath.c b/src/backend/utils/adt/jsonpath.c
index 762f7e8a09d..f3f2119a4a8 100644
--- a/src/backend/utils/adt/jsonpath.c
+++ b/src/backend/utils/adt/jsonpath.c
@@ -298,6 +298,8 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 		case jpiMod:
 		case jpiStartsWith:
 		case jpiDecimal:
+		case jpiStrReplace:
+		case jpiStrSplitPart:
 			{
 				/*
 				 * First, reserve place for left/right arg's positions, then
@@ -362,6 +364,9 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 		case jpiTimeTz:
 		case jpiTimestamp:
 		case jpiTimestampTz:
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
 			{
 				int32		arg = reserveSpaceForItemPointer(buf);
 
@@ -457,6 +462,9 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 		case jpiInteger:
 		case jpiNumber:
 		case jpiStringFunc:
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrInitcap:
 			break;
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", item->type);
@@ -831,6 +839,60 @@ printJsonPathItem(StringInfo buf, JsonPathItem *v, bool inKey,
 			}
 			appendStringInfoChar(buf, ')');
 			break;
+		case jpiStrReplace:
+			appendStringInfoString(buf, ".replace(");
+			jspGetLeftArg(v, &elem);
+			printJsonPathItem(buf, &elem, false, false);
+			appendStringInfoChar(buf, ',');
+			jspGetRightArg(v, &elem);
+			printJsonPathItem(buf, &elem, false, false);
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrSplitPart:
+			appendStringInfoString(buf, ".split_part(");
+			jspGetLeftArg(v, &elem);
+			printJsonPathItem(buf, &elem, false, false);
+			appendStringInfoChar(buf, ',');
+			jspGetRightArg(v, &elem);
+			printJsonPathItem(buf, &elem, false, false);
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrLower:
+			appendStringInfoString(buf, ".lower()");
+			break;
+		case jpiStrUpper:
+			appendStringInfoString(buf, ".upper()");
+			break;
+		case jpiStrInitcap:
+			appendStringInfoString(buf, ".initcap()");
+			break;
+		case jpiStrLtrim:
+			appendStringInfoString(buf, ".ltrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrRtrim:
+			appendStringInfoString(buf, ".rtrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrBtrim:
+			appendStringInfoString(buf, ".btrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", v->type);
 	}
@@ -906,6 +968,12 @@ jspOperationName(JsonPathItemType type)
 			return "number";
 		case jpiStringFunc:
 			return "string";
+		case jpiStrReplace:
+			return "replace";
+		case jpiStrLower:
+			return "lower";
+		case jpiStrUpper:
+			return "upper";
 		case jpiTime:
 			return "time";
 		case jpiTimeTz:
@@ -914,6 +982,16 @@ jspOperationName(JsonPathItemType type)
 			return "timestamp";
 		case jpiTimestampTz:
 			return "timestamp_tz";
+		case jpiStrLtrim:
+			return "ltrim";
+		case jpiStrRtrim:
+			return "rtrim";
+		case jpiStrBtrim:
+			return "btrim";
+		case jpiStrInitcap:
+			return "initcap";
+		case jpiStrSplitPart:
+			return "split_part";
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", type);
 			return NULL;
@@ -1016,6 +1094,9 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 		case jpiInteger:
 		case jpiNumber:
 		case jpiStringFunc:
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrInitcap:
 			break;
 		case jpiString:
 		case jpiKey:
@@ -1041,6 +1122,8 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 		case jpiMod:
 		case jpiStartsWith:
 		case jpiDecimal:
+		case jpiStrReplace:
+		case jpiStrSplitPart:
 			read_int32(v->content.args.left, base, pos);
 			read_int32(v->content.args.right, base, pos);
 			break;
@@ -1055,6 +1138,9 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 		case jpiTimeTz:
 		case jpiTimestamp:
 		case jpiTimestampTz:
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
 			read_int32(v->content.arg, base, pos);
 			break;
 		case jpiIndexArray:
@@ -1090,7 +1176,10 @@ jspGetArg(JsonPathItem *v, JsonPathItem *a)
 		   v->type == jpiTime ||
 		   v->type == jpiTimeTz ||
 		   v->type == jpiTimestamp ||
-		   v->type == jpiTimestampTz);
+		   v->type == jpiTimestampTz ||
+		   v->type == jpiStrLtrim ||
+		   v->type == jpiStrRtrim ||
+		   v->type == jpiStrBtrim);
 
 	jspInitByBuffer(a, v->base, v->content.arg);
 }
@@ -1149,10 +1238,18 @@ jspGetNext(JsonPathItem *v, JsonPathItem *a)
 			   v->type == jpiInteger ||
 			   v->type == jpiNumber ||
 			   v->type == jpiStringFunc ||
+			   v->type == jpiStrReplace ||
+			   v->type == jpiStrLower ||
+			   v->type == jpiStrUpper ||
 			   v->type == jpiTime ||
 			   v->type == jpiTimeTz ||
 			   v->type == jpiTimestamp ||
-			   v->type == jpiTimestampTz);
+			   v->type == jpiTimestampTz ||
+			   v->type == jpiStrLtrim ||
+			   v->type == jpiStrRtrim ||
+			   v->type == jpiStrBtrim ||
+			   v->type == jpiStrInitcap ||
+			   v->type == jpiStrSplitPart);
 
 		if (a)
 			jspInitByBuffer(a, v->base, v->nextPos);
@@ -1179,7 +1276,9 @@ jspGetLeftArg(JsonPathItem *v, JsonPathItem *a)
 		   v->type == jpiDiv ||
 		   v->type == jpiMod ||
 		   v->type == jpiStartsWith ||
-		   v->type == jpiDecimal);
+		   v->type == jpiDecimal ||
+		   v->type == jpiStrReplace ||
+		   v->type == jpiStrSplitPart);
 
 	jspInitByBuffer(a, v->base, v->content.args.left);
 }
@@ -1201,7 +1300,9 @@ jspGetRightArg(JsonPathItem *v, JsonPathItem *a)
 		   v->type == jpiDiv ||
 		   v->type == jpiMod ||
 		   v->type == jpiStartsWith ||
-		   v->type == jpiDecimal);
+		   v->type == jpiDecimal ||
+		   v->type == jpiStrReplace ||
+		   v->type == jpiStrSplitPart);
 
 	jspInitByBuffer(a, v->base, v->content.args.right);
 }
@@ -1501,6 +1602,14 @@ jspIsMutableWalker(JsonPathItem *jpi, struct JsonPathMutableContext *cxt)
 			case jpiInteger:
 			case jpiNumber:
 			case jpiStringFunc:
+			case jpiStrReplace:
+			case jpiStrLower:
+			case jpiStrUpper:
+			case jpiStrLtrim:
+			case jpiStrRtrim:
+			case jpiStrBtrim:
+			case jpiStrInitcap:
+			case jpiStrSplitPart:
 				status = jpdsNonDateTime;
 				break;
 
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 8156695e97e..c22917796da 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -302,6 +302,8 @@ static JsonPathExecResult executeNumericItemMethod(JsonPathExecContext *cxt,
 												   JsonValueList *found);
 static JsonPathExecResult executeDateTimeMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
 												JsonbValue *jb, JsonValueList *found);
+static JsonPathExecResult executeStringInternalMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
+													  JsonbValue *jb, JsonValueList *found);
 static JsonPathExecResult executeKeyValueMethod(JsonPathExecContext *cxt,
 												JsonPathItem *jsp, JsonbValue *jb, JsonValueList *found);
 static JsonPathExecResult appendBoolResult(JsonPathExecContext *cxt,
@@ -1661,6 +1663,23 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
 			}
 			break;
 
+		case jpiStrLtrim:
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrReplace:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
+		case jpiStrInitcap:
+		case jpiStrSplitPart:
+			{
+				if (unwrap && JsonbType(jb) == jbvArray)
+					return executeItemUnwrapTargetArray(cxt, jsp, jb, found, false);
+
+				return executeStringInternalMethod(cxt, jsp, jb, found);
+			}
+			break;
+
+
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", jsp->type);
 	}
@@ -2794,6 +2813,194 @@ executeDateTimeMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
 	return executeNextItem(cxt, jsp, &elem, jb, found, hasNext);
 }
 
+/*
+ * Implementation of .upper(), lower() et. al. methods,
+ * that forward their actual implementation to internal functions.
+ */
+static JsonPathExecResult
+executeStringInternalMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
+							JsonbValue *jb, JsonValueList *found)
+{
+	JsonbValue	jbvbuf;
+	bool		hasNext;
+	JsonPathExecResult res = jperNotFound;
+	JsonPathItem elem;
+	Datum		str;			/* Datum representation for the current string
+								 * value. The first argument to internal
+								 * functions */
+	char	   *tmp = NULL;
+	char	   *resStr = NULL;
+
+	Assert(jsp->type == jpiStrLower ||
+		   jsp->type == jpiStrUpper ||
+		   jsp->type == jpiStrReplace ||
+		   jsp->type == jpiStrLtrim ||
+		   jsp->type == jpiStrRtrim ||
+		   jsp->type == jpiStrBtrim ||
+		   jsp->type == jpiStrInitcap ||
+		   jsp->type == jpiStrSplitPart);
+
+	if (!(jb = getScalar(jb, jbvString)))
+		RETURN_ERROR(ereport(ERROR,
+							 (errcode(ERRCODE_INVALID_ARGUMENT_FOR_SQL_JSON_DATETIME_FUNCTION),
+							  errmsg("jsonpath item method .%s() can only be applied to a string",
+									 jspOperationName(jsp->type)))));
+
+	tmp = pnstrdup(jb->val.string.val, jb->val.string.len);
+	str = CStringGetTextDatum(tmp);
+
+	/* Internal string functions that accept no arguments */
+	switch (jsp->type)
+	{
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
+			{
+				char	   *characters_str;
+				int			characters_len;
+				PGFunction	func = NULL;
+
+				if (jsp->content.arg)
+				{
+					switch (jsp->type)
+					{
+						case jpiStrLtrim:
+							func = ltrim;
+							break;
+						case jpiStrRtrim:
+							func = rtrim;
+							break;
+						case jpiStrBtrim:
+							func = btrim;
+							break;
+						default:;
+					}
+					jspGetArg(jsp, &elem);
+					if (elem.type != jpiString)
+						elog(ERROR, "invalid jsonpath item type for .%s() argument", jspOperationName(jsp->type));
+
+					characters_str = jspGetString(&elem, &characters_len);
+					resStr = TextDatumGetCString(DirectFunctionCall2Coll(func,
+																		 DEFAULT_COLLATION_OID, str,
+																		 CStringGetTextDatum(characters_str)));
+					break;
+				}
+
+				switch (jsp->type)
+				{
+					case jpiStrLtrim:
+						func = ltrim1;
+						break;
+					case jpiStrRtrim:
+						func = rtrim1;
+						break;
+					case jpiStrBtrim:
+						func = btrim1;
+						break;
+					default:;
+				}
+				resStr = TextDatumGetCString(DirectFunctionCall1Coll(func,
+																	 DEFAULT_COLLATION_OID, str));
+				break;
+			}
+
+		case jpiStrLower:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(lower, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiStrUpper:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(upper, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiStrInitcap:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(initcap, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiStrReplace:
+			{
+				char	   *from_str,
+						   *to_str;
+				int			from_len,
+							to_len;
+
+				jspGetLeftArg(jsp, &elem);
+				if (elem.type != jpiString)
+					elog(ERROR, "invalid jsonpath item type for .replace() from");
+
+				from_str = jspGetString(&elem, &from_len);
+
+				jspGetRightArg(jsp, &elem);
+				if (elem.type != jpiString)
+					elog(ERROR, "invalid jsonpath item type for .replace() to");
+
+				to_str = jspGetString(&elem, &to_len);
+
+				resStr = TextDatumGetCString(DirectFunctionCall3Coll(replace_text,
+																	 C_COLLATION_OID,
+																	 CStringGetTextDatum(tmp),
+																	 CStringGetTextDatum(from_str),
+																	 CStringGetTextDatum(to_str)));
+				break;
+			}
+		case jpiStrSplitPart:
+			{
+				char	   *from_str;
+				Numeric		n;
+				int			from_len;
+
+				jspGetLeftArg(jsp, &elem);
+				if (elem.type != jpiString)
+					elog(ERROR, "invalid jsonpath item type for .split_part()");
+
+				from_str = jspGetString(&elem, &from_len);
+
+				jspGetRightArg(jsp, &elem);
+				if (elem.type != jpiNumeric)
+					elog(ERROR, "invalid jsonpath item type for .split_part()");
+
+				n = jspGetNumeric(&elem);
+
+				resStr = TextDatumGetCString(DirectFunctionCall3Coll(split_part,
+																	 C_COLLATION_OID,
+																	 CStringGetTextDatum(tmp),
+																	 CStringGetTextDatum(from_str),
+																	 DirectFunctionCall1(numeric_int4, NumericGetDatum(n))));
+				break;
+			}
+		default:
+			elog(ERROR, "unsupported jsonpath item type: %d", jsp->type);
+	}
+
+	if (resStr)
+		res = jperOk;
+
+	hasNext = jspGetNext(jsp, &elem);
+
+	if (!hasNext && !found)
+		return res;
+
+	jb = hasNext ? &jbvbuf : palloc(sizeof(*jb));
+
+	/* Create the appropriate jb value to return */
+	switch (jsp->type)
+	{
+			/* Cases for functions that return text */
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrReplace:
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
+		case jpiStrInitcap:
+		case jpiStrSplitPart:
+			jb->type = jbvString;
+			jb->val.string.val = resStr;
+			jb->val.string.len = strlen(jb->val.string.val);
+		default:
+			;
+			/* cant' happen */
+	}
+
+	return executeNextItem(cxt, jsp, &elem, jb, found, hasNext);
+}
+
 /*
  * Implementation of .keyvalue() method.
  *
diff --git a/src/backend/utils/adt/jsonpath_gram.y b/src/backend/utils/adt/jsonpath_gram.y
index 0b16cec18c4..53bf779e152 100644
--- a/src/backend/utils/adt/jsonpath_gram.y
+++ b/src/backend/utils/adt/jsonpath_gram.y
@@ -86,6 +86,8 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 %token	<str>		DATETIME_P
 %token	<str>		BIGINT_P BOOLEAN_P DATE_P DECIMAL_P INTEGER_P NUMBER_P
 %token	<str>		STRINGFUNC_P TIME_P TIME_TZ_P TIMESTAMP_P TIMESTAMP_TZ_P
+%token	<str>		STR_REPLACE_P STR_LOWER_P STR_UPPER_P STR_LTRIM_P STR_RTRIM_P STR_BTRIM_P
+					STR_INITCAP_P STR_SPLIT_PART_P
 
 %type	<result>	result
 
@@ -95,7 +97,7 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 					str_elem opt_str_arg int_elem
 					uint_elem opt_uint_arg
 
-%type	<elems>		accessor_expr int_list opt_int_list
+%type	<elems>		accessor_expr int_list opt_int_list str_int_args str_str_args
 
 %type	<indexs>	index_list
 
@@ -278,6 +280,16 @@ accessor_op:
 		{ $$ = makeItemUnary(jpiTimestamp, $4); }
 	| '.' TIMESTAMP_TZ_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimestampTz, $4); }
+	| '.' STR_REPLACE_P '(' str_str_args ')'
+		{ $$ = makeItemBinary(jpiStrReplace, linitial($4), lsecond($4)); }
+	| '.' STR_SPLIT_PART_P '(' str_int_args ')'
+		{ $$ = makeItemBinary(jpiStrSplitPart, linitial($4), lsecond($4)); }
+	| '.' STR_LTRIM_P '(' opt_str_arg ')'
+		{ $$ = makeItemUnary(jpiStrLtrim, $4); }
+	| '.' STR_RTRIM_P '(' opt_str_arg ')'
+		{ $$ = makeItemUnary(jpiStrRtrim, $4); }
+	| '.' STR_BTRIM_P '(' opt_str_arg ')'
+		{ $$ = makeItemUnary(jpiStrBtrim, $4); }
 	;
 
 int_elem:
@@ -317,6 +329,14 @@ opt_str_arg:
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
+str_int_args:
+	str_elem ',' int_elem			{ $$ = list_make2($1, $3); }
+	;
+
+str_str_args:
+	str_elem ',' str_elem 			{ $$ = list_make2($1, $3); }
+	;
+
 key:
 	key_name						{ $$ = makeItemKey(&$1); }
 	;
@@ -357,6 +377,9 @@ key_name:
 	| TIME_TZ_P
 	| TIMESTAMP_P
 	| TIMESTAMP_TZ_P
+	| STR_LTRIM_P
+	| STR_RTRIM_P
+	| STR_BTRIM_P
 	;
 
 method:
@@ -373,6 +396,9 @@ method:
 	| INTEGER_P						{ $$ = jpiInteger; }
 	| NUMBER_P						{ $$ = jpiNumber; }
 	| STRINGFUNC_P					{ $$ = jpiStringFunc; }
+	| STR_LOWER_P					{ $$ = jpiStrLower; }
+	| STR_UPPER_P					{ $$ = jpiStrUpper; }
+	| STR_INITCAP_P					{ $$ = jpiStrInitcap; }
 	;
 %%
 
diff --git a/src/backend/utils/adt/jsonpath_scan.l b/src/backend/utils/adt/jsonpath_scan.l
index c7aab83eeb4..69c61f98500 100644
--- a/src/backend/utils/adt/jsonpath_scan.l
+++ b/src/backend/utils/adt/jsonpath_scan.l
@@ -413,8 +413,13 @@ static const JsonPathKeyword keywords[] = {
 	{4, true, TRUE_P, "true"},
 	{4, false, TYPE_P, "type"},
 	{4, false, WITH_P, "with"},
+	{5, false, STR_BTRIM_P, "btrim"},
 	{5, true, FALSE_P, "false"},
 	{5, false, FLOOR_P, "floor"},
+	{5, false, STR_LOWER_P, "lower"},
+	{5, false, STR_LTRIM_P, "ltrim"},
+	{5, false, STR_RTRIM_P, "rtrim"},
+	{5, false, STR_UPPER_P, "upper"},
 	{6, false, BIGINT_P, "bigint"},
 	{6, false, DOUBLE_P, "double"},
 	{6, false, EXISTS_P, "exists"},
@@ -425,13 +430,16 @@ static const JsonPathKeyword keywords[] = {
 	{7, false, BOOLEAN_P, "boolean"},
 	{7, false, CEILING_P, "ceiling"},
 	{7, false, DECIMAL_P, "decimal"},
+	{7, false, STR_INITCAP_P, "initcap"},
 	{7, false, INTEGER_P, "integer"},
+	{7, false, STR_REPLACE_P, "replace"},
 	{7, false, TIME_TZ_P, "time_tz"},
 	{7, false, UNKNOWN_P, "unknown"},
 	{8, false, DATETIME_P, "datetime"},
 	{8, false, KEYVALUE_P, "keyvalue"},
 	{9, false, TIMESTAMP_P, "timestamp"},
 	{10, false, LIKE_REGEX_P, "like_regex"},
+	{10,false, STR_SPLIT_PART_P, "split_part"},
 	{12, false, TIMESTAMP_TZ_P, "timestamp_tz"},
 };
 
diff --git a/src/include/utils/jsonpath.h b/src/include/utils/jsonpath.h
index 23a76d233e9..2d0c53f7b06 100644
--- a/src/include/utils/jsonpath.h
+++ b/src/include/utils/jsonpath.h
@@ -115,6 +115,14 @@ typedef enum JsonPathItemType
 	jpiTimeTz,					/* .time_tz() item method */
 	jpiTimestamp,				/* .timestamp() item method */
 	jpiTimestampTz,				/* .timestamp_tz() item method */
+	jpiStrReplace,				/* .replace() item method */
+	jpiStrLower,				/* .lower() item method */
+	jpiStrUpper,				/* .upper() item method */
+	jpiStrLtrim,				/* .ltrim() item method */
+	jpiStrRtrim,				/* .rtrim() item method */
+	jpiStrBtrim,				/* .btrim() item method */
+	jpiStrInitcap,				/* .initcap() item method */
+	jpiStrSplitPart,			/* .split_part() item method */
 } JsonPathItemType;
 
 /* XQuery regex mode flags for LIKE_REGEX predicate */
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e91a29..cea539717f9 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -2723,6 +2723,405 @@ select jsonb_path_query('"2023-08-15 12:34:56"', '$.timestamp().string()');
 (1 row)
 
 rollback;
+-- test .ltrim()
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"zzzytest"', '$.ltrim("xyz")');
+ jsonb_path_query 
+------------------
+ "test"
+(1 row)
+
+select jsonb_path_query('null', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('null', '$.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.ltrim()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('{}', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('true', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('1234', '$.ltrim().type()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim()');
+  jsonb_path_query_array  
+--------------------------
+ ["maybe  ", "yes", "no"]
+(1 row)
+
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .rtrim()
+select jsonb_path_query('"   hello   "', '$.rtrim(" ")');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+select jsonb_path_query('"testxxzx"', '$.rtrim("xyz")');
+ jsonb_path_query 
+------------------
+ "test"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+-- test .btrim()
+select jsonb_path_query('"   hello   "', '$.btrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+select jsonb_path_query('"xyxtrimyyx"', '$.btrim("xyz")');
+ jsonb_path_query 
+------------------
+ "trim"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.btrim()');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.btrim()');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+-- test .lower()
+select jsonb_path_query('null', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('null', '$.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.lower()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('{}', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.lower()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.lower()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('true', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('1234', '$.lower().type()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower()');
+ jsonb_path_query_array 
+------------------------
+ ["maybe", "yes", "no"]
+(1 row)
+
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .upper()
+select jsonb_path_query('null', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('null', '$.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.upper()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('{}', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.upper()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.upper()');
+ jsonb_path_query 
+------------------
+ "1.23AAA"
+(1 row)
+
+select jsonb_path_query('1234', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('true', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('1234', '$.upper().type()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper()');
+ jsonb_path_query_array 
+------------------------
+ ["MAYBE", "YES", "NO"]
+(1 row)
+
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .initcap()
+select jsonb_path_query('null', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('null', '$.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.initcap()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('{}', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('true', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('1234', '$.initcap().type()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('["maybe yes", "probably no"]', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "Maybe Yes"
+ "Probably No"
+(2 rows)
+
+-- Test .replace()
+select jsonb_path_query('null', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('null', '$.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('["x", "y", "z"]', '$.replace("x", "bye")');
+ jsonb_path_query 
+------------------
+ "bye"
+ "y"
+ "z"
+(3 rows)
+
+select jsonb_path_query('{}', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('"hello world"', '$.replace("hello","bye")');
+ jsonb_path_query 
+------------------
+ "bye world"
+(1 row)
+
+select jsonb_path_query('"hello world"', '$.replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
+-- Test .split_part()
+select jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)');
+ jsonb_path_query 
+------------------
+ "def"
+(1 row)
+
+select jsonb_path_query('"abc,def,ghi,jkl"', '$.split_part(",", -2)');
+ jsonb_path_query 
+------------------
+ "ghi"
+(1 row)
+
+-- Test string methods play nicely together
+select jsonb_path_query('"hello world"', '$.replace("hello","bye").upper()');
+ jsonb_path_query 
+------------------
+ "BYE WORLD"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye")');
+ jsonb_path_query 
+------------------
+ "bye world"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.upper().lower().upper().replace("HELLO", "BYE")');
+ jsonb_path_query 
+------------------
+ "BYE WORLD"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
+select jsonb_path_query('"   hElLo WorlD "', '$.btrim().lower().upper().lower().replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
 -- Test .time()
 select jsonb_path_query('null', '$.time()');
 ERROR:  jsonpath item method .time() can only be applied to a string
diff --git a/src/test/regress/expected/jsonpath.out b/src/test/regress/expected/jsonpath.out
index fd9bd755f52..a13022feabd 100644
--- a/src/test/regress/expected/jsonpath.out
+++ b/src/test/regress/expected/jsonpath.out
@@ -435,6 +435,143 @@ select '$.string()'::jsonpath;
  $.string()
 (1 row)
 
+select '$.replace("hello","bye")'::jsonpath;
+         jsonpath         
+--------------------------
+ $.replace("hello","bye")
+(1 row)
+
+select '$.lower()'::jsonpath;
+ jsonpath  
+-----------
+ $.lower()
+(1 row)
+
+select '$.upper()'::jsonpath;
+ jsonpath  
+-----------
+ $.upper()
+(1 row)
+
+select '$.lower().upper().lower().replace("hello","bye")'::jsonpath;
+                     jsonpath                     
+--------------------------------------------------
+ $.lower().upper().lower().replace("hello","bye")
+(1 row)
+
+select '$.ltrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.ltrim()
+(1 row)
+
+select '$.ltrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.ltrim("xyz")
+(1 row)
+
+select '$.rtrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.rtrim()
+(1 row)
+
+select '$.rtrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.rtrim("xyz")
+(1 row)
+
+select '$.btrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.btrim()
+(1 row)
+
+select '$.btrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.btrim("xyz")
+(1 row)
+
+select '$.initcap()'::jsonpath;
+  jsonpath   
+-------------
+ $.initcap()
+(1 row)
+
+select '$.split_part("~@~", 2)'::jsonpath;
+       jsonpath        
+-----------------------
+ $.split_part("~@~",2)
+(1 row)
+
+-- Parse errors
+select '$.replace("hello")'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.replace("hello")'::jsonpath;
+               ^
+select '$.replace()'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.replace()'::jsonpath;
+               ^
+select '$.replace("hello","bye","extra")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.replace("hello","bye","extra")'::jsonpath;
+               ^
+select '$.split_part("~@~")'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.split_part("~@~")'::jsonpath;
+               ^
+select '$.split_part()'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.split_part()'::jsonpath;
+               ^
+select '$.split_part("~@~", "hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.split_part("~@~", "hi")'::jsonpath;
+               ^
+select '$.split_part("~@~", 2, "extra")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.split_part("~@~", 2, "extra")'::jsonpath;
+               ^
+select '$.lower("hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.lower("hi")'::jsonpath;
+               ^
+select '$.upper("hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.upper("hi")'::jsonpath;
+               ^
+select '$.initcap("hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.initcap("hi")'::jsonpath;
+               ^
+select '$.ltrim(42)'::jsonpath;
+ERROR:  syntax error at or near "42" of jsonpath input
+LINE 1: select '$.ltrim(42)'::jsonpath;
+               ^
+select '$.ltrim("x", "y")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.ltrim("x", "y")'::jsonpath;
+               ^
+select '$.rtrim(42)'::jsonpath;
+ERROR:  syntax error at or near "42" of jsonpath input
+LINE 1: select '$.rtrim(42)'::jsonpath;
+               ^
+select '$.rtrim("x", "y")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.rtrim("x", "y")'::jsonpath;
+               ^
+select '$.trim(42)'::jsonpath;
+ERROR:  syntax error at or near "(" of jsonpath input
+LINE 1: select '$.trim(42)'::jsonpath;
+               ^
+select '$.trim("x", "y")'::jsonpath;
+ERROR:  syntax error at or near "(" of jsonpath input
+LINE 1: select '$.trim("x", "y")'::jsonpath;
+               ^
 select '$.time()'::jsonpath;
  jsonpath 
 ----------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a5269..8169719343e 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -623,6 +623,115 @@ select jsonb_path_query('"2023-08-15 12:34:56 +5:30"', '$.timestamp_tz().string(
 select jsonb_path_query('"2023-08-15 12:34:56"', '$.timestamp().string()');
 rollback;
 
+-- test .ltrim()
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+select jsonb_path_query('"   hello   "', '$.ltrim()');
+select jsonb_path_query('"zzzytest"', '$.ltrim("xyz")');
+select jsonb_path_query('null', '$.ltrim()');
+select jsonb_path_query('null', '$.ltrim()', silent => true);
+select jsonb_path_query('[]', '$.ltrim()');
+select jsonb_path_query('[]', 'strict $.ltrim()');
+select jsonb_path_query('{}', '$.ltrim()');
+select jsonb_path_query('[]', 'strict $.ltrim()', silent => true);
+select jsonb_path_query('{}', '$.ltrim()', silent => true);
+select jsonb_path_query('1.23', '$.ltrim()');
+select jsonb_path_query('"1.23"', '$.ltrim()');
+select jsonb_path_query('"1.23aaa"', '$.ltrim()');
+select jsonb_path_query('1234', '$.ltrim()');
+select jsonb_path_query('true', '$.ltrim()');
+select jsonb_path_query('1234', '$.ltrim().type()');
+select jsonb_path_query('[2, true]', '$.ltrim()');
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim()');
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim().type()');
+
+-- test .rtrim()
+select jsonb_path_query('"   hello   "', '$.rtrim(" ")');
+select jsonb_path_query('"testxxzx"', '$.rtrim("xyz")');
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+
+-- test .btrim()
+select jsonb_path_query('"   hello   "', '$.btrim(" ")');
+select jsonb_path_query('"xyxtrimyyx"', '$.btrim("xyz")');
+select jsonb_path_query('"   hello   "', '$.btrim()');
+select jsonb_path_query('"   hello   "', '$.btrim()');
+
+-- test .lower()
+select jsonb_path_query('null', '$.lower()');
+select jsonb_path_query('null', '$.lower()', silent => true);
+select jsonb_path_query('[]', '$.lower()');
+select jsonb_path_query('[]', 'strict $.lower()');
+select jsonb_path_query('{}', '$.lower()');
+select jsonb_path_query('[]', 'strict $.lower()', silent => true);
+select jsonb_path_query('{}', '$.lower()', silent => true);
+select jsonb_path_query('1.23', '$.lower()');
+select jsonb_path_query('"1.23"', '$.lower()');
+select jsonb_path_query('"1.23aaa"', '$.lower()');
+select jsonb_path_query('1234', '$.lower()');
+select jsonb_path_query('true', '$.lower()');
+select jsonb_path_query('1234', '$.lower().type()');
+select jsonb_path_query('[2, true]', '$.lower()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower().type()');
+
+-- test .upper()
+select jsonb_path_query('null', '$.upper()');
+select jsonb_path_query('null', '$.upper()', silent => true);
+select jsonb_path_query('[]', '$.upper()');
+select jsonb_path_query('[]', 'strict $.upper()');
+select jsonb_path_query('{}', '$.upper()');
+select jsonb_path_query('[]', 'strict $.upper()', silent => true);
+select jsonb_path_query('{}', '$.upper()', silent => true);
+select jsonb_path_query('1.23', '$.upper()');
+select jsonb_path_query('"1.23"', '$.upper()');
+select jsonb_path_query('"1.23aaa"', '$.upper()');
+select jsonb_path_query('1234', '$.upper()');
+select jsonb_path_query('true', '$.upper()');
+select jsonb_path_query('1234', '$.upper().type()');
+select jsonb_path_query('[2, true]', '$.upper()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper().type()');
+
+-- test .initcap()
+select jsonb_path_query('null', '$.initcap()');
+select jsonb_path_query('null', '$.initcap()', silent => true);
+select jsonb_path_query('[]', '$.initcap()');
+select jsonb_path_query('[]', 'strict $.initcap()');
+select jsonb_path_query('{}', '$.initcap()');
+select jsonb_path_query('[]', 'strict $.initcap()', silent => true);
+select jsonb_path_query('{}', '$.initcap()', silent => true);
+select jsonb_path_query('1.23', '$.initcap()');
+select jsonb_path_query('"1.23"', '$.initcap()');
+select jsonb_path_query('"1.23aaa"', '$.initcap()');
+select jsonb_path_query('1234', '$.initcap()');
+select jsonb_path_query('true', '$.initcap()');
+select jsonb_path_query('1234', '$.initcap().type()');
+select jsonb_path_query('[2, true]', '$.initcap()');
+select jsonb_path_query('["maybe yes", "probably no"]', '$.initcap()');
+
+-- Test .replace()
+select jsonb_path_query('null', '$.replace("x", "bye")');
+select jsonb_path_query('null', '$.replace("x", "bye")', silent => true);
+select jsonb_path_query('["x", "y", "z"]', '$.replace("x", "bye")');
+select jsonb_path_query('{}', '$.replace("x", "bye")');
+select jsonb_path_query('[]', 'strict $.replace("x", "bye")', silent => true);
+select jsonb_path_query('{}', '$.replace("x", "bye")', silent => true);
+select jsonb_path_query('1.23', '$.replace("x", "bye")');
+select jsonb_path_query('"hello world"', '$.replace("hello","bye")');
+select jsonb_path_query('"hello world"', '$.replace("hello","bye") starts with "bye"');
+
+-- Test .split_part()
+select jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)');
+select jsonb_path_query('"abc,def,ghi,jkl"', '$.split_part(",", -2)');
+
+-- Test string methods play nicely together
+select jsonb_path_query('"hello world"', '$.replace("hello","bye").upper()');
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye")');
+select jsonb_path_query('"hElLo WorlD"', '$.upper().lower().upper().replace("HELLO", "BYE")');
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye") starts with "bye"');
+select jsonb_path_query('"   hElLo WorlD "', '$.btrim().lower().upper().lower().replace("hello","bye") starts with "bye"');
+
 -- Test .time()
 select jsonb_path_query('null', '$.time()');
 select jsonb_path_query('true', '$.time()');
diff --git a/src/test/regress/sql/jsonpath.sql b/src/test/regress/sql/jsonpath.sql
index 61a5270d4e8..7dd2e57e7a6 100644
--- a/src/test/regress/sql/jsonpath.sql
+++ b/src/test/regress/sql/jsonpath.sql
@@ -78,6 +78,37 @@ select '$.boolean()'::jsonpath;
 select '$.date()'::jsonpath;
 select '$.decimal(4,2)'::jsonpath;
 select '$.string()'::jsonpath;
+select '$.replace("hello","bye")'::jsonpath;
+select '$.lower()'::jsonpath;
+select '$.upper()'::jsonpath;
+select '$.lower().upper().lower().replace("hello","bye")'::jsonpath;
+select '$.ltrim()'::jsonpath;
+select '$.ltrim("xyz")'::jsonpath;
+select '$.rtrim()'::jsonpath;
+select '$.rtrim("xyz")'::jsonpath;
+select '$.btrim()'::jsonpath;
+select '$.btrim("xyz")'::jsonpath;
+select '$.initcap()'::jsonpath;
+select '$.split_part("~@~", 2)'::jsonpath;
+
+-- Parse errors
+select '$.replace("hello")'::jsonpath;
+select '$.replace()'::jsonpath;
+select '$.replace("hello","bye","extra")'::jsonpath;
+select '$.split_part("~@~")'::jsonpath;
+select '$.split_part()'::jsonpath;
+select '$.split_part("~@~", "hi")'::jsonpath;
+select '$.split_part("~@~", 2, "extra")'::jsonpath;
+select '$.lower("hi")'::jsonpath;
+select '$.upper("hi")'::jsonpath;
+select '$.initcap("hi")'::jsonpath;
+select '$.ltrim(42)'::jsonpath;
+select '$.ltrim("x", "y")'::jsonpath;
+select '$.rtrim(42)'::jsonpath;
+select '$.rtrim("x", "y")'::jsonpath;
+select '$.trim(42)'::jsonpath;
+select '$.trim("x", "y")'::jsonpath;
+
 select '$.time()'::jsonpath;
 select '$.time(6)'::jsonpath;
 select '$.time_tz()'::jsonpath;
-- 
2.47.3

From 9a89826825a7098e0a1c17a84d92774e1965868f Mon Sep 17 00:00:00 2001
From: "David E. Wheeler" <david@justatheory.com>
Date: Mon, 2 Jun 2025 17:14:10 -0400
Subject: [PATCH v14 1/2] Rename jsonpath method arg tokens

Rename the `csv_` tokens to `int_`, because they represent signed or
unsigned integers, as follows:

*   `csv_elem` => `int_elem`
*   `csv_list` => `int_list`
*   `opt_csv_list` => `opt_int_list`

Rename the `datetime_precision` tokens to `uint_arg`, as they represent
unsigned integers and will be useful for other methods in the future, as
follows:

*   `datetime_precision` => `uint_elem`
*   `opt_datetime_precision` => `opt_uint_arg`

Rename the `datetime_template` tokens to `str_arg`, as they represent
strings and will be useful for other methods in the future, as follows:

*   `datetime_template` => `str_elem`
*   `opt_datetime_template` => `opt_str_arg`
---
 src/backend/utils/adt/jsonpath_gram.y | 42 +++++++++++++--------------
 1 file changed, 21 insertions(+), 21 deletions(-)

diff --git a/src/backend/utils/adt/jsonpath_gram.y b/src/backend/utils/adt/jsonpath_gram.y
index 499745a8fef..0b16cec18c4 100644
--- a/src/backend/utils/adt/jsonpath_gram.y
+++ b/src/backend/utils/adt/jsonpath_gram.y
@@ -92,10 +92,10 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 %type	<value>		scalar_value path_primary expr array_accessor
 					any_path accessor_op key predicate delimited_predicate
 					index_elem starts_with_initial expr_or_predicate
-					datetime_template opt_datetime_template csv_elem
-					datetime_precision opt_datetime_precision
+					str_elem opt_str_arg int_elem
+					uint_elem opt_uint_arg
 
-%type	<elems>		accessor_expr csv_list opt_csv_list
+%type	<elems>		accessor_expr int_list opt_int_list
 
 %type	<indexs>	index_list
 
@@ -254,7 +254,7 @@ accessor_op:
 	| '.' any_path					{ $$ = $2; }
 	| '.' method '(' ')'			{ $$ = makeItemType($2); }
 	| '?' '(' predicate ')'			{ $$ = makeItemUnary(jpiFilter, $3); }
-	| '.' DECIMAL_P '(' opt_csv_list ')'
+	| '.' DECIMAL_P '(' opt_int_list ')'
 		{
 			if (list_length($4) == 0)
 				$$ = makeItemBinary(jpiDecimal, NULL, NULL);
@@ -268,19 +268,19 @@ accessor_op:
 						 errmsg("invalid input syntax for type %s", "jsonpath"),
 						 errdetail(".decimal() can only have an optional precision[,scale].")));
 		}
-	| '.' DATETIME_P '(' opt_datetime_template ')'
+	| '.' DATETIME_P '(' opt_str_arg ')'
 		{ $$ = makeItemUnary(jpiDatetime, $4); }
-	| '.' TIME_P '(' opt_datetime_precision ')'
+	| '.' TIME_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTime, $4); }
-	| '.' TIME_TZ_P '(' opt_datetime_precision ')'
+	| '.' TIME_TZ_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimeTz, $4); }
-	| '.' TIMESTAMP_P '(' opt_datetime_precision ')'
+	| '.' TIMESTAMP_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimestamp, $4); }
-	| '.' TIMESTAMP_TZ_P '(' opt_datetime_precision ')'
+	| '.' TIMESTAMP_TZ_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimestampTz, $4); }
 	;
 
-csv_elem:
+int_elem:
 	INT_P
 		{ $$ = makeItemNumeric(&$1); }
 	| '+' INT_P %prec UMINUS
@@ -289,31 +289,31 @@ csv_elem:
 		{ $$ = makeItemUnary(jpiMinus, makeItemNumeric(&$2)); }
 	;
 
-csv_list:
-	csv_elem						{ $$ = list_make1($1); }
-	| csv_list ',' csv_elem			{ $$ = lappend($1, $3); }
+int_list:
+	int_elem						{ $$ = list_make1($1); }
+	| int_list ',' int_elem			{ $$ = lappend($1, $3); }
 	;
 
-opt_csv_list:
-	csv_list						{ $$ = $1; }
+opt_int_list:
+	int_list						{ $$ = $1; }
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
-datetime_precision:
+uint_elem:
 	INT_P							{ $$ = makeItemNumeric(&$1); }
 	;
 
-opt_datetime_precision:
-	datetime_precision				{ $$ = $1; }
+opt_uint_arg:
+	uint_elem						{ $$ = $1; }
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
-datetime_template:
+str_elem:
 	STRING_P						{ $$ = makeItemString(&$1); }
 	;
 
-opt_datetime_template:
-	datetime_template				{ $$ = $1; }
+opt_str_arg:
+	str_elem						{ $$ = $1; }
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
-- 
2.51.0

From 50e867f73fcff05d3919014db67e65ec21b322ef Mon Sep 17 00:00:00 2001
From: Florents Tselai <florents.tselai@gmail.com>
Date: Fri, 11 Jul 2025 14:04:28 -0400
Subject: [PATCH v14 2/2] Add additional jsonpath string methods

Add the following jsonpath methods:

*   l/r/btrim()
*   lower(), upper()
*   initcap()
*   replace()
*   split_part()

Each simply dispatches to the standard string processing functions.
These depend on the locale, but since it's set at `initdb`, they can be
considered immutable and therefore allowed in any jsonpath expression.
---
 doc/src/sgml/func/func-json.sgml             | 140 +++++++
 src/backend/utils/adt/jsonpath.c             | 117 +++++-
 src/backend/utils/adt/jsonpath_exec.c        | 209 ++++++++++
 src/backend/utils/adt/jsonpath_gram.y        |  28 +-
 src/backend/utils/adt/jsonpath_scan.l        |   8 +
 src/include/utils/jsonpath.h                 |   8 +
 src/test/regress/expected/jsonb_jsonpath.out | 399 +++++++++++++++++++
 src/test/regress/expected/jsonpath.out       | 137 +++++++
 src/test/regress/sql/jsonb_jsonpath.sql      | 109 +++++
 src/test/regress/sql/jsonpath.sql            |  31 ++
 10 files changed, 1181 insertions(+), 5 deletions(-)

diff --git a/doc/src/sgml/func/func-json.sgml b/doc/src/sgml/func/func-json.sgml
index b9316ba0ee5..49031820c4b 100644
--- a/doc/src/sgml/func/func-json.sgml
+++ b/doc/src/sgml/func/func-json.sgml
@@ -2781,6 +2781,146 @@ ERROR:  jsonpath member accessor can only be applied to an object
         <returnvalue>[{"id": 0, "key": "x", "value": "20"}, {"id": 0, "key": "y", "value": 32}]</returnvalue>
        </para></entry>
       </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>lower()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String converted to all lower case according to the rules of the database's locale.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"TOM"', '$.lower()')</literal>
+        <returnvalue>"tom"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>upper()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String converted to all upper case according to the rules of the database's locale.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"tom"', '$.upper()')</literal>
+        <returnvalue>"TOM"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>initcap()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the first letter of each word converted to upper case
+        according to the rules of the database's locale. Words are sequences
+        of alphanumeric characters separated by non-alphanumeric characters.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"hi THOMAS"', '$.initcap()')</literal>
+        <returnvalue>"Hi Thomas"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>replace(<replaceable>from</replaceable>, <replaceable>to</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with all occurrences of substring from replaced with substring to.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"abcdefabcdef"', '$.replace("cd", "XX")')</literal>
+        <returnvalue>"abXXefabXXef"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>split_part(<replaceable>delimiter</replaceable>, <replaceable>n</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String split at occurrences of <replaceable>delimiter</replaceable>
+        and returns the <replaceable>n</replaceable>'th field (counting from
+        one) or, when <replaceable>n</replaceable> is negative, returns the
+        |<replaceable>n</replaceable>|'th-from-last field.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)')</literal>
+        <returnvalue>"def"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"abc,def,ghi,jkl"', '$.split_part(",", 2)')</literal>
+        <returnvalue>"ghi"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>ltrim(<replaceable>characters</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the longest string containing only spaces or the
+        characters in <replaceable>characters</replaceable> removed from the
+        start of <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal> jsonb_path_query('"  hello"', '$.ltrim()')</literal>
+        <returnvalue>"hello"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"zzzytest"', '$.ltrim("xyz")')</literal>
+        <returnvalue>"test"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>rtrim([ <replaceable>characters</replaceable> ])</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the longest string containing only spaces or the
+        characters in <replaceable>characters</replaceable> removed from the
+        end of <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"hello  "', '$.rtrim()')</literal>
+        <returnvalue>"hello"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"testxxzx"', '$.rtrim("xyz")')</literal>
+        <returnvalue>"test"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>btrim([ <replaceable>characters</replaceable> ])</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the longest string containing only spaces or the
+        characters in <replaceable>characters</replaceable> removed from the
+        start and end of <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"  hello  "', '$.btrim()')</literal>
+        <returnvalue>"hello"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"xyxtrimyyx"', '$.btrim("xyz")')</literal>
+        <returnvalue>"trim"</returnvalue>
+       </para></entry>
+      </row>
+
      </tbody>
     </tgroup>
    </table>
diff --git a/src/backend/utils/adt/jsonpath.c b/src/backend/utils/adt/jsonpath.c
index 762f7e8a09d..f3f2119a4a8 100644
--- a/src/backend/utils/adt/jsonpath.c
+++ b/src/backend/utils/adt/jsonpath.c
@@ -298,6 +298,8 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 		case jpiMod:
 		case jpiStartsWith:
 		case jpiDecimal:
+		case jpiStrReplace:
+		case jpiStrSplitPart:
 			{
 				/*
 				 * First, reserve place for left/right arg's positions, then
@@ -362,6 +364,9 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 		case jpiTimeTz:
 		case jpiTimestamp:
 		case jpiTimestampTz:
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
 			{
 				int32		arg = reserveSpaceForItemPointer(buf);
 
@@ -457,6 +462,9 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 		case jpiInteger:
 		case jpiNumber:
 		case jpiStringFunc:
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrInitcap:
 			break;
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", item->type);
@@ -831,6 +839,60 @@ printJsonPathItem(StringInfo buf, JsonPathItem *v, bool inKey,
 			}
 			appendStringInfoChar(buf, ')');
 			break;
+		case jpiStrReplace:
+			appendStringInfoString(buf, ".replace(");
+			jspGetLeftArg(v, &elem);
+			printJsonPathItem(buf, &elem, false, false);
+			appendStringInfoChar(buf, ',');
+			jspGetRightArg(v, &elem);
+			printJsonPathItem(buf, &elem, false, false);
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrSplitPart:
+			appendStringInfoString(buf, ".split_part(");
+			jspGetLeftArg(v, &elem);
+			printJsonPathItem(buf, &elem, false, false);
+			appendStringInfoChar(buf, ',');
+			jspGetRightArg(v, &elem);
+			printJsonPathItem(buf, &elem, false, false);
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrLower:
+			appendStringInfoString(buf, ".lower()");
+			break;
+		case jpiStrUpper:
+			appendStringInfoString(buf, ".upper()");
+			break;
+		case jpiStrInitcap:
+			appendStringInfoString(buf, ".initcap()");
+			break;
+		case jpiStrLtrim:
+			appendStringInfoString(buf, ".ltrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrRtrim:
+			appendStringInfoString(buf, ".rtrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrBtrim:
+			appendStringInfoString(buf, ".btrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", v->type);
 	}
@@ -906,6 +968,12 @@ jspOperationName(JsonPathItemType type)
 			return "number";
 		case jpiStringFunc:
 			return "string";
+		case jpiStrReplace:
+			return "replace";
+		case jpiStrLower:
+			return "lower";
+		case jpiStrUpper:
+			return "upper";
 		case jpiTime:
 			return "time";
 		case jpiTimeTz:
@@ -914,6 +982,16 @@ jspOperationName(JsonPathItemType type)
 			return "timestamp";
 		case jpiTimestampTz:
 			return "timestamp_tz";
+		case jpiStrLtrim:
+			return "ltrim";
+		case jpiStrRtrim:
+			return "rtrim";
+		case jpiStrBtrim:
+			return "btrim";
+		case jpiStrInitcap:
+			return "initcap";
+		case jpiStrSplitPart:
+			return "split_part";
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", type);
 			return NULL;
@@ -1016,6 +1094,9 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 		case jpiInteger:
 		case jpiNumber:
 		case jpiStringFunc:
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrInitcap:
 			break;
 		case jpiString:
 		case jpiKey:
@@ -1041,6 +1122,8 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 		case jpiMod:
 		case jpiStartsWith:
 		case jpiDecimal:
+		case jpiStrReplace:
+		case jpiStrSplitPart:
 			read_int32(v->content.args.left, base, pos);
 			read_int32(v->content.args.right, base, pos);
 			break;
@@ -1055,6 +1138,9 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 		case jpiTimeTz:
 		case jpiTimestamp:
 		case jpiTimestampTz:
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
 			read_int32(v->content.arg, base, pos);
 			break;
 		case jpiIndexArray:
@@ -1090,7 +1176,10 @@ jspGetArg(JsonPathItem *v, JsonPathItem *a)
 		   v->type == jpiTime ||
 		   v->type == jpiTimeTz ||
 		   v->type == jpiTimestamp ||
-		   v->type == jpiTimestampTz);
+		   v->type == jpiTimestampTz ||
+		   v->type == jpiStrLtrim ||
+		   v->type == jpiStrRtrim ||
+		   v->type == jpiStrBtrim);
 
 	jspInitByBuffer(a, v->base, v->content.arg);
 }
@@ -1149,10 +1238,18 @@ jspGetNext(JsonPathItem *v, JsonPathItem *a)
 			   v->type == jpiInteger ||
 			   v->type == jpiNumber ||
 			   v->type == jpiStringFunc ||
+			   v->type == jpiStrReplace ||
+			   v->type == jpiStrLower ||
+			   v->type == jpiStrUpper ||
 			   v->type == jpiTime ||
 			   v->type == jpiTimeTz ||
 			   v->type == jpiTimestamp ||
-			   v->type == jpiTimestampTz);
+			   v->type == jpiTimestampTz ||
+			   v->type == jpiStrLtrim ||
+			   v->type == jpiStrRtrim ||
+			   v->type == jpiStrBtrim ||
+			   v->type == jpiStrInitcap ||
+			   v->type == jpiStrSplitPart);
 
 		if (a)
 			jspInitByBuffer(a, v->base, v->nextPos);
@@ -1179,7 +1276,9 @@ jspGetLeftArg(JsonPathItem *v, JsonPathItem *a)
 		   v->type == jpiDiv ||
 		   v->type == jpiMod ||
 		   v->type == jpiStartsWith ||
-		   v->type == jpiDecimal);
+		   v->type == jpiDecimal ||
+		   v->type == jpiStrReplace ||
+		   v->type == jpiStrSplitPart);
 
 	jspInitByBuffer(a, v->base, v->content.args.left);
 }
@@ -1201,7 +1300,9 @@ jspGetRightArg(JsonPathItem *v, JsonPathItem *a)
 		   v->type == jpiDiv ||
 		   v->type == jpiMod ||
 		   v->type == jpiStartsWith ||
-		   v->type == jpiDecimal);
+		   v->type == jpiDecimal ||
+		   v->type == jpiStrReplace ||
+		   v->type == jpiStrSplitPart);
 
 	jspInitByBuffer(a, v->base, v->content.args.right);
 }
@@ -1501,6 +1602,14 @@ jspIsMutableWalker(JsonPathItem *jpi, struct JsonPathMutableContext *cxt)
 			case jpiInteger:
 			case jpiNumber:
 			case jpiStringFunc:
+			case jpiStrReplace:
+			case jpiStrLower:
+			case jpiStrUpper:
+			case jpiStrLtrim:
+			case jpiStrRtrim:
+			case jpiStrBtrim:
+			case jpiStrInitcap:
+			case jpiStrSplitPart:
 				status = jpdsNonDateTime;
 				break;
 
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 8156695e97e..093374867ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -302,6 +302,8 @@ static JsonPathExecResult executeNumericItemMethod(JsonPathExecContext *cxt,
 												   JsonValueList *found);
 static JsonPathExecResult executeDateTimeMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
 												JsonbValue *jb, JsonValueList *found);
+static JsonPathExecResult executeStringInternalMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
+													  JsonbValue *jb, JsonValueList *found);
 static JsonPathExecResult executeKeyValueMethod(JsonPathExecContext *cxt,
 												JsonPathItem *jsp, JsonbValue *jb, JsonValueList *found);
 static JsonPathExecResult appendBoolResult(JsonPathExecContext *cxt,
@@ -1661,6 +1663,23 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
 			}
 			break;
 
+		case jpiStrLtrim:
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrReplace:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
+		case jpiStrInitcap:
+		case jpiStrSplitPart:
+			{
+				if (unwrap && JsonbType(jb) == jbvArray)
+					return executeItemUnwrapTargetArray(cxt, jsp, jb, found, false);
+
+				return executeStringInternalMethod(cxt, jsp, jb, found);
+			}
+			break;
+
+
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", jsp->type);
 	}
@@ -2794,6 +2813,196 @@ executeDateTimeMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
 	return executeNextItem(cxt, jsp, &elem, jb, found, hasNext);
 }
 
+/*
+ * Implementation of .upper(), lower() et. al. methods,
+ * that forward their actual implementation to internal functions.
+ */
+static JsonPathExecResult
+executeStringInternalMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
+							JsonbValue *jb, JsonValueList *found)
+{
+	JsonbValue	jbvbuf;
+	bool		hasNext;
+	JsonPathExecResult res = jperNotFound;
+	JsonPathItem elem;
+	Datum		str;			/* Datum representation for the current string
+								 * value. The first argument to internal
+								 * functions */
+	char	   *tmp = NULL;
+	char	   *resStr = NULL;
+
+	Assert(jsp->type == jpiStrLower ||
+		   jsp->type == jpiStrUpper ||
+		   jsp->type == jpiStrReplace ||
+		   jsp->type == jpiStrLtrim ||
+		   jsp->type == jpiStrRtrim ||
+		   jsp->type == jpiStrBtrim ||
+		   jsp->type == jpiStrInitcap ||
+		   jsp->type == jpiStrSplitPart);
+
+	if (!(jb = getScalar(jb, jbvString)))
+		RETURN_ERROR(ereport(ERROR,
+							 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+							  errmsg("jsonpath item method .%s() can only be applied to a string",
+									 jspOperationName(jsp->type)))));
+
+	tmp = pnstrdup(jb->val.string.val, jb->val.string.len);
+	str = CStringGetTextDatum(tmp);
+
+	/* Internal string functions that accept no arguments */
+	switch (jsp->type)
+	{
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
+			{
+				char	   *characters_str;
+				int			characters_len;
+				PGFunction	func = NULL;
+
+				if (jsp->content.arg)
+				{
+					switch (jsp->type)
+					{
+						case jpiStrLtrim:
+							func = ltrim;
+							break;
+						case jpiStrRtrim:
+							func = rtrim;
+							break;
+						case jpiStrBtrim:
+							func = btrim;
+							break;
+						default:;
+					}
+					jspGetArg(jsp, &elem);
+					if (elem.type != jpiString)
+						elog(ERROR, "invalid jsonpath item type for .%s() argument", jspOperationName(jsp->type));
+
+					characters_str = jspGetString(&elem, &characters_len);
+					resStr = TextDatumGetCString(DirectFunctionCall2Coll(func,
+																		 DEFAULT_COLLATION_OID, str,
+																		 CStringGetTextDatum(characters_str)));
+					break;
+				}
+
+				switch (jsp->type)
+				{
+					case jpiStrLtrim:
+						func = ltrim1;
+						break;
+					case jpiStrRtrim:
+						func = rtrim1;
+						break;
+					case jpiStrBtrim:
+						func = btrim1;
+						break;
+					default:;
+				}
+				resStr = TextDatumGetCString(DirectFunctionCall1Coll(func,
+																	 DEFAULT_COLLATION_OID, str));
+				break;
+			}
+
+		case jpiStrLower:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(lower, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiStrUpper:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(upper, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiStrInitcap:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(initcap, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiStrReplace:
+			{
+				char	   *from_str,
+						   *to_str;
+				int			from_len,
+							to_len;
+
+				jspGetLeftArg(jsp, &elem);
+				if (elem.type != jpiString)
+					elog(ERROR, "invalid jsonpath item type for .replace() from");
+
+				from_str = jspGetString(&elem, &from_len);
+
+				jspGetRightArg(jsp, &elem);
+				if (elem.type != jpiString)
+					elog(ERROR, "invalid jsonpath item type for .replace() to");
+
+				to_str = jspGetString(&elem, &to_len);
+
+				resStr = TextDatumGetCString(DirectFunctionCall3Coll(replace_text,
+																	 DEFAULT_COLLATION_OID,
+																	 CStringGetTextDatum(tmp),
+																	 CStringGetTextDatum(from_str),
+																	 CStringGetTextDatum(to_str)));
+				break;
+			}
+		case jpiStrSplitPart:
+			{
+				char	   *from_str;
+				Numeric		n;
+				int			from_len;
+
+				jspGetLeftArg(jsp, &elem);
+				if (elem.type != jpiString)
+					elog(ERROR, "invalid jsonpath item type for .split_part()");
+
+				from_str = jspGetString(&elem, &from_len);
+
+				jspGetRightArg(jsp, &elem);
+				if (elem.type != jpiNumeric)
+					elog(ERROR, "invalid jsonpath item type for .split_part()");
+
+				n = jspGetNumeric(&elem);
+
+				resStr = TextDatumGetCString(DirectFunctionCall3Coll(split_part,
+																	 C_COLLATION_OID,
+																	 CStringGetTextDatum(tmp),
+																	 CStringGetTextDatum(from_str),
+																	 DirectFunctionCall1(numeric_int4, NumericGetDatum(n))));
+				break;
+			}
+		default:
+			elog(ERROR, "unsupported jsonpath item type: %d", jsp->type);
+	}
+
+	if (resStr)
+		res = jperOk;
+
+	hasNext = jspGetNext(jsp, &elem);
+
+	if (!hasNext && !found)
+		return res;
+
+	jb = hasNext ? &jbvbuf : palloc(sizeof(*jb));
+
+	/* Create the appropriate jb value to return */
+	switch (jsp->type)
+	{
+			/* Cases for functions that return text */
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrReplace:
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
+		case jpiStrInitcap:
+		case jpiStrSplitPart:
+			jb->type = jbvString;
+			jb->val.string.val = resStr;
+			jb->val.string.len = strlen(jb->val.string.val);
+			break;
+		default:
+			;
+			/* do nothing */
+			Assert(false);
+	}
+
+	return executeNextItem(cxt, jsp, &elem, jb, found, hasNext);
+}
+
 /*
  * Implementation of .keyvalue() method.
  *
diff --git a/src/backend/utils/adt/jsonpath_gram.y b/src/backend/utils/adt/jsonpath_gram.y
index 0b16cec18c4..53bf779e152 100644
--- a/src/backend/utils/adt/jsonpath_gram.y
+++ b/src/backend/utils/adt/jsonpath_gram.y
@@ -86,6 +86,8 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 %token	<str>		DATETIME_P
 %token	<str>		BIGINT_P BOOLEAN_P DATE_P DECIMAL_P INTEGER_P NUMBER_P
 %token	<str>		STRINGFUNC_P TIME_P TIME_TZ_P TIMESTAMP_P TIMESTAMP_TZ_P
+%token	<str>		STR_REPLACE_P STR_LOWER_P STR_UPPER_P STR_LTRIM_P STR_RTRIM_P STR_BTRIM_P
+					STR_INITCAP_P STR_SPLIT_PART_P
 
 %type	<result>	result
 
@@ -95,7 +97,7 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 					str_elem opt_str_arg int_elem
 					uint_elem opt_uint_arg
 
-%type	<elems>		accessor_expr int_list opt_int_list
+%type	<elems>		accessor_expr int_list opt_int_list str_int_args str_str_args
 
 %type	<indexs>	index_list
 
@@ -278,6 +280,16 @@ accessor_op:
 		{ $$ = makeItemUnary(jpiTimestamp, $4); }
 	| '.' TIMESTAMP_TZ_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimestampTz, $4); }
+	| '.' STR_REPLACE_P '(' str_str_args ')'
+		{ $$ = makeItemBinary(jpiStrReplace, linitial($4), lsecond($4)); }
+	| '.' STR_SPLIT_PART_P '(' str_int_args ')'
+		{ $$ = makeItemBinary(jpiStrSplitPart, linitial($4), lsecond($4)); }
+	| '.' STR_LTRIM_P '(' opt_str_arg ')'
+		{ $$ = makeItemUnary(jpiStrLtrim, $4); }
+	| '.' STR_RTRIM_P '(' opt_str_arg ')'
+		{ $$ = makeItemUnary(jpiStrRtrim, $4); }
+	| '.' STR_BTRIM_P '(' opt_str_arg ')'
+		{ $$ = makeItemUnary(jpiStrBtrim, $4); }
 	;
 
 int_elem:
@@ -317,6 +329,14 @@ opt_str_arg:
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
+str_int_args:
+	str_elem ',' int_elem			{ $$ = list_make2($1, $3); }
+	;
+
+str_str_args:
+	str_elem ',' str_elem 			{ $$ = list_make2($1, $3); }
+	;
+
 key:
 	key_name						{ $$ = makeItemKey(&$1); }
 	;
@@ -357,6 +377,9 @@ key_name:
 	| TIME_TZ_P
 	| TIMESTAMP_P
 	| TIMESTAMP_TZ_P
+	| STR_LTRIM_P
+	| STR_RTRIM_P
+	| STR_BTRIM_P
 	;
 
 method:
@@ -373,6 +396,9 @@ method:
 	| INTEGER_P						{ $$ = jpiInteger; }
 	| NUMBER_P						{ $$ = jpiNumber; }
 	| STRINGFUNC_P					{ $$ = jpiStringFunc; }
+	| STR_LOWER_P					{ $$ = jpiStrLower; }
+	| STR_UPPER_P					{ $$ = jpiStrUpper; }
+	| STR_INITCAP_P					{ $$ = jpiStrInitcap; }
 	;
 %%
 
diff --git a/src/backend/utils/adt/jsonpath_scan.l b/src/backend/utils/adt/jsonpath_scan.l
index c7aab83eeb4..69c61f98500 100644
--- a/src/backend/utils/adt/jsonpath_scan.l
+++ b/src/backend/utils/adt/jsonpath_scan.l
@@ -413,8 +413,13 @@ static const JsonPathKeyword keywords[] = {
 	{4, true, TRUE_P, "true"},
 	{4, false, TYPE_P, "type"},
 	{4, false, WITH_P, "with"},
+	{5, false, STR_BTRIM_P, "btrim"},
 	{5, true, FALSE_P, "false"},
 	{5, false, FLOOR_P, "floor"},
+	{5, false, STR_LOWER_P, "lower"},
+	{5, false, STR_LTRIM_P, "ltrim"},
+	{5, false, STR_RTRIM_P, "rtrim"},
+	{5, false, STR_UPPER_P, "upper"},
 	{6, false, BIGINT_P, "bigint"},
 	{6, false, DOUBLE_P, "double"},
 	{6, false, EXISTS_P, "exists"},
@@ -425,13 +430,16 @@ static const JsonPathKeyword keywords[] = {
 	{7, false, BOOLEAN_P, "boolean"},
 	{7, false, CEILING_P, "ceiling"},
 	{7, false, DECIMAL_P, "decimal"},
+	{7, false, STR_INITCAP_P, "initcap"},
 	{7, false, INTEGER_P, "integer"},
+	{7, false, STR_REPLACE_P, "replace"},
 	{7, false, TIME_TZ_P, "time_tz"},
 	{7, false, UNKNOWN_P, "unknown"},
 	{8, false, DATETIME_P, "datetime"},
 	{8, false, KEYVALUE_P, "keyvalue"},
 	{9, false, TIMESTAMP_P, "timestamp"},
 	{10, false, LIKE_REGEX_P, "like_regex"},
+	{10,false, STR_SPLIT_PART_P, "split_part"},
 	{12, false, TIMESTAMP_TZ_P, "timestamp_tz"},
 };
 
diff --git a/src/include/utils/jsonpath.h b/src/include/utils/jsonpath.h
index 23a76d233e9..2d0c53f7b06 100644
--- a/src/include/utils/jsonpath.h
+++ b/src/include/utils/jsonpath.h
@@ -115,6 +115,14 @@ typedef enum JsonPathItemType
 	jpiTimeTz,					/* .time_tz() item method */
 	jpiTimestamp,				/* .timestamp() item method */
 	jpiTimestampTz,				/* .timestamp_tz() item method */
+	jpiStrReplace,				/* .replace() item method */
+	jpiStrLower,				/* .lower() item method */
+	jpiStrUpper,				/* .upper() item method */
+	jpiStrLtrim,				/* .ltrim() item method */
+	jpiStrRtrim,				/* .rtrim() item method */
+	jpiStrBtrim,				/* .btrim() item method */
+	jpiStrInitcap,				/* .initcap() item method */
+	jpiStrSplitPart,			/* .split_part() item method */
 } JsonPathItemType;
 
 /* XQuery regex mode flags for LIKE_REGEX predicate */
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e91a29..cea539717f9 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -2723,6 +2723,405 @@ select jsonb_path_query('"2023-08-15 12:34:56"', '$.timestamp().string()');
 (1 row)
 
 rollback;
+-- test .ltrim()
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"zzzytest"', '$.ltrim("xyz")');
+ jsonb_path_query 
+------------------
+ "test"
+(1 row)
+
+select jsonb_path_query('null', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('null', '$.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.ltrim()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('{}', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('true', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('1234', '$.ltrim().type()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim()');
+  jsonb_path_query_array  
+--------------------------
+ ["maybe  ", "yes", "no"]
+(1 row)
+
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .rtrim()
+select jsonb_path_query('"   hello   "', '$.rtrim(" ")');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+select jsonb_path_query('"testxxzx"', '$.rtrim("xyz")');
+ jsonb_path_query 
+------------------
+ "test"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+-- test .btrim()
+select jsonb_path_query('"   hello   "', '$.btrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+select jsonb_path_query('"xyxtrimyyx"', '$.btrim("xyz")');
+ jsonb_path_query 
+------------------
+ "trim"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.btrim()');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.btrim()');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+-- test .lower()
+select jsonb_path_query('null', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('null', '$.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.lower()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('{}', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.lower()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.lower()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('true', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('1234', '$.lower().type()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower()');
+ jsonb_path_query_array 
+------------------------
+ ["maybe", "yes", "no"]
+(1 row)
+
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .upper()
+select jsonb_path_query('null', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('null', '$.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.upper()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('{}', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.upper()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.upper()');
+ jsonb_path_query 
+------------------
+ "1.23AAA"
+(1 row)
+
+select jsonb_path_query('1234', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('true', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('1234', '$.upper().type()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper()');
+ jsonb_path_query_array 
+------------------------
+ ["MAYBE", "YES", "NO"]
+(1 row)
+
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .initcap()
+select jsonb_path_query('null', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('null', '$.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.initcap()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('{}', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('true', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('1234', '$.initcap().type()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('["maybe yes", "probably no"]', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "Maybe Yes"
+ "Probably No"
+(2 rows)
+
+-- Test .replace()
+select jsonb_path_query('null', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('null', '$.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('["x", "y", "z"]', '$.replace("x", "bye")');
+ jsonb_path_query 
+------------------
+ "bye"
+ "y"
+ "z"
+(3 rows)
+
+select jsonb_path_query('{}', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('"hello world"', '$.replace("hello","bye")');
+ jsonb_path_query 
+------------------
+ "bye world"
+(1 row)
+
+select jsonb_path_query('"hello world"', '$.replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
+-- Test .split_part()
+select jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)');
+ jsonb_path_query 
+------------------
+ "def"
+(1 row)
+
+select jsonb_path_query('"abc,def,ghi,jkl"', '$.split_part(",", -2)');
+ jsonb_path_query 
+------------------
+ "ghi"
+(1 row)
+
+-- Test string methods play nicely together
+select jsonb_path_query('"hello world"', '$.replace("hello","bye").upper()');
+ jsonb_path_query 
+------------------
+ "BYE WORLD"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye")');
+ jsonb_path_query 
+------------------
+ "bye world"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.upper().lower().upper().replace("HELLO", "BYE")');
+ jsonb_path_query 
+------------------
+ "BYE WORLD"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
+select jsonb_path_query('"   hElLo WorlD "', '$.btrim().lower().upper().lower().replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
 -- Test .time()
 select jsonb_path_query('null', '$.time()');
 ERROR:  jsonpath item method .time() can only be applied to a string
diff --git a/src/test/regress/expected/jsonpath.out b/src/test/regress/expected/jsonpath.out
index fd9bd755f52..a13022feabd 100644
--- a/src/test/regress/expected/jsonpath.out
+++ b/src/test/regress/expected/jsonpath.out
@@ -435,6 +435,143 @@ select '$.string()'::jsonpath;
  $.string()
 (1 row)
 
+select '$.replace("hello","bye")'::jsonpath;
+         jsonpath         
+--------------------------
+ $.replace("hello","bye")
+(1 row)
+
+select '$.lower()'::jsonpath;
+ jsonpath  
+-----------
+ $.lower()
+(1 row)
+
+select '$.upper()'::jsonpath;
+ jsonpath  
+-----------
+ $.upper()
+(1 row)
+
+select '$.lower().upper().lower().replace("hello","bye")'::jsonpath;
+                     jsonpath                     
+--------------------------------------------------
+ $.lower().upper().lower().replace("hello","bye")
+(1 row)
+
+select '$.ltrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.ltrim()
+(1 row)
+
+select '$.ltrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.ltrim("xyz")
+(1 row)
+
+select '$.rtrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.rtrim()
+(1 row)
+
+select '$.rtrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.rtrim("xyz")
+(1 row)
+
+select '$.btrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.btrim()
+(1 row)
+
+select '$.btrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.btrim("xyz")
+(1 row)
+
+select '$.initcap()'::jsonpath;
+  jsonpath   
+-------------
+ $.initcap()
+(1 row)
+
+select '$.split_part("~@~", 2)'::jsonpath;
+       jsonpath        
+-----------------------
+ $.split_part("~@~",2)
+(1 row)
+
+-- Parse errors
+select '$.replace("hello")'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.replace("hello")'::jsonpath;
+               ^
+select '$.replace()'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.replace()'::jsonpath;
+               ^
+select '$.replace("hello","bye","extra")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.replace("hello","bye","extra")'::jsonpath;
+               ^
+select '$.split_part("~@~")'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.split_part("~@~")'::jsonpath;
+               ^
+select '$.split_part()'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.split_part()'::jsonpath;
+               ^
+select '$.split_part("~@~", "hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.split_part("~@~", "hi")'::jsonpath;
+               ^
+select '$.split_part("~@~", 2, "extra")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.split_part("~@~", 2, "extra")'::jsonpath;
+               ^
+select '$.lower("hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.lower("hi")'::jsonpath;
+               ^
+select '$.upper("hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.upper("hi")'::jsonpath;
+               ^
+select '$.initcap("hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.initcap("hi")'::jsonpath;
+               ^
+select '$.ltrim(42)'::jsonpath;
+ERROR:  syntax error at or near "42" of jsonpath input
+LINE 1: select '$.ltrim(42)'::jsonpath;
+               ^
+select '$.ltrim("x", "y")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.ltrim("x", "y")'::jsonpath;
+               ^
+select '$.rtrim(42)'::jsonpath;
+ERROR:  syntax error at or near "42" of jsonpath input
+LINE 1: select '$.rtrim(42)'::jsonpath;
+               ^
+select '$.rtrim("x", "y")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.rtrim("x", "y")'::jsonpath;
+               ^
+select '$.trim(42)'::jsonpath;
+ERROR:  syntax error at or near "(" of jsonpath input
+LINE 1: select '$.trim(42)'::jsonpath;
+               ^
+select '$.trim("x", "y")'::jsonpath;
+ERROR:  syntax error at or near "(" of jsonpath input
+LINE 1: select '$.trim("x", "y")'::jsonpath;
+               ^
 select '$.time()'::jsonpath;
  jsonpath 
 ----------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a5269..8169719343e 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -623,6 +623,115 @@ select jsonb_path_query('"2023-08-15 12:34:56 +5:30"', '$.timestamp_tz().string(
 select jsonb_path_query('"2023-08-15 12:34:56"', '$.timestamp().string()');
 rollback;
 
+-- test .ltrim()
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+select jsonb_path_query('"   hello   "', '$.ltrim()');
+select jsonb_path_query('"zzzytest"', '$.ltrim("xyz")');
+select jsonb_path_query('null', '$.ltrim()');
+select jsonb_path_query('null', '$.ltrim()', silent => true);
+select jsonb_path_query('[]', '$.ltrim()');
+select jsonb_path_query('[]', 'strict $.ltrim()');
+select jsonb_path_query('{}', '$.ltrim()');
+select jsonb_path_query('[]', 'strict $.ltrim()', silent => true);
+select jsonb_path_query('{}', '$.ltrim()', silent => true);
+select jsonb_path_query('1.23', '$.ltrim()');
+select jsonb_path_query('"1.23"', '$.ltrim()');
+select jsonb_path_query('"1.23aaa"', '$.ltrim()');
+select jsonb_path_query('1234', '$.ltrim()');
+select jsonb_path_query('true', '$.ltrim()');
+select jsonb_path_query('1234', '$.ltrim().type()');
+select jsonb_path_query('[2, true]', '$.ltrim()');
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim()');
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim().type()');
+
+-- test .rtrim()
+select jsonb_path_query('"   hello   "', '$.rtrim(" ")');
+select jsonb_path_query('"testxxzx"', '$.rtrim("xyz")');
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+
+-- test .btrim()
+select jsonb_path_query('"   hello   "', '$.btrim(" ")');
+select jsonb_path_query('"xyxtrimyyx"', '$.btrim("xyz")');
+select jsonb_path_query('"   hello   "', '$.btrim()');
+select jsonb_path_query('"   hello   "', '$.btrim()');
+
+-- test .lower()
+select jsonb_path_query('null', '$.lower()');
+select jsonb_path_query('null', '$.lower()', silent => true);
+select jsonb_path_query('[]', '$.lower()');
+select jsonb_path_query('[]', 'strict $.lower()');
+select jsonb_path_query('{}', '$.lower()');
+select jsonb_path_query('[]', 'strict $.lower()', silent => true);
+select jsonb_path_query('{}', '$.lower()', silent => true);
+select jsonb_path_query('1.23', '$.lower()');
+select jsonb_path_query('"1.23"', '$.lower()');
+select jsonb_path_query('"1.23aaa"', '$.lower()');
+select jsonb_path_query('1234', '$.lower()');
+select jsonb_path_query('true', '$.lower()');
+select jsonb_path_query('1234', '$.lower().type()');
+select jsonb_path_query('[2, true]', '$.lower()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower().type()');
+
+-- test .upper()
+select jsonb_path_query('null', '$.upper()');
+select jsonb_path_query('null', '$.upper()', silent => true);
+select jsonb_path_query('[]', '$.upper()');
+select jsonb_path_query('[]', 'strict $.upper()');
+select jsonb_path_query('{}', '$.upper()');
+select jsonb_path_query('[]', 'strict $.upper()', silent => true);
+select jsonb_path_query('{}', '$.upper()', silent => true);
+select jsonb_path_query('1.23', '$.upper()');
+select jsonb_path_query('"1.23"', '$.upper()');
+select jsonb_path_query('"1.23aaa"', '$.upper()');
+select jsonb_path_query('1234', '$.upper()');
+select jsonb_path_query('true', '$.upper()');
+select jsonb_path_query('1234', '$.upper().type()');
+select jsonb_path_query('[2, true]', '$.upper()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper().type()');
+
+-- test .initcap()
+select jsonb_path_query('null', '$.initcap()');
+select jsonb_path_query('null', '$.initcap()', silent => true);
+select jsonb_path_query('[]', '$.initcap()');
+select jsonb_path_query('[]', 'strict $.initcap()');
+select jsonb_path_query('{}', '$.initcap()');
+select jsonb_path_query('[]', 'strict $.initcap()', silent => true);
+select jsonb_path_query('{}', '$.initcap()', silent => true);
+select jsonb_path_query('1.23', '$.initcap()');
+select jsonb_path_query('"1.23"', '$.initcap()');
+select jsonb_path_query('"1.23aaa"', '$.initcap()');
+select jsonb_path_query('1234', '$.initcap()');
+select jsonb_path_query('true', '$.initcap()');
+select jsonb_path_query('1234', '$.initcap().type()');
+select jsonb_path_query('[2, true]', '$.initcap()');
+select jsonb_path_query('["maybe yes", "probably no"]', '$.initcap()');
+
+-- Test .replace()
+select jsonb_path_query('null', '$.replace("x", "bye")');
+select jsonb_path_query('null', '$.replace("x", "bye")', silent => true);
+select jsonb_path_query('["x", "y", "z"]', '$.replace("x", "bye")');
+select jsonb_path_query('{}', '$.replace("x", "bye")');
+select jsonb_path_query('[]', 'strict $.replace("x", "bye")', silent => true);
+select jsonb_path_query('{}', '$.replace("x", "bye")', silent => true);
+select jsonb_path_query('1.23', '$.replace("x", "bye")');
+select jsonb_path_query('"hello world"', '$.replace("hello","bye")');
+select jsonb_path_query('"hello world"', '$.replace("hello","bye") starts with "bye"');
+
+-- Test .split_part()
+select jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)');
+select jsonb_path_query('"abc,def,ghi,jkl"', '$.split_part(",", -2)');
+
+-- Test string methods play nicely together
+select jsonb_path_query('"hello world"', '$.replace("hello","bye").upper()');
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye")');
+select jsonb_path_query('"hElLo WorlD"', '$.upper().lower().upper().replace("HELLO", "BYE")');
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye") starts with "bye"');
+select jsonb_path_query('"   hElLo WorlD "', '$.btrim().lower().upper().lower().replace("hello","bye") starts with "bye"');
+
 -- Test .time()
 select jsonb_path_query('null', '$.time()');
 select jsonb_path_query('true', '$.time()');
diff --git a/src/test/regress/sql/jsonpath.sql b/src/test/regress/sql/jsonpath.sql
index 61a5270d4e8..7dd2e57e7a6 100644
--- a/src/test/regress/sql/jsonpath.sql
+++ b/src/test/regress/sql/jsonpath.sql
@@ -78,6 +78,37 @@ select '$.boolean()'::jsonpath;
 select '$.date()'::jsonpath;
 select '$.decimal(4,2)'::jsonpath;
 select '$.string()'::jsonpath;
+select '$.replace("hello","bye")'::jsonpath;
+select '$.lower()'::jsonpath;
+select '$.upper()'::jsonpath;
+select '$.lower().upper().lower().replace("hello","bye")'::jsonpath;
+select '$.ltrim()'::jsonpath;
+select '$.ltrim("xyz")'::jsonpath;
+select '$.rtrim()'::jsonpath;
+select '$.rtrim("xyz")'::jsonpath;
+select '$.btrim()'::jsonpath;
+select '$.btrim("xyz")'::jsonpath;
+select '$.initcap()'::jsonpath;
+select '$.split_part("~@~", 2)'::jsonpath;
+
+-- Parse errors
+select '$.replace("hello")'::jsonpath;
+select '$.replace()'::jsonpath;
+select '$.replace("hello","bye","extra")'::jsonpath;
+select '$.split_part("~@~")'::jsonpath;
+select '$.split_part()'::jsonpath;
+select '$.split_part("~@~", "hi")'::jsonpath;
+select '$.split_part("~@~", 2, "extra")'::jsonpath;
+select '$.lower("hi")'::jsonpath;
+select '$.upper("hi")'::jsonpath;
+select '$.initcap("hi")'::jsonpath;
+select '$.ltrim(42)'::jsonpath;
+select '$.ltrim("x", "y")'::jsonpath;
+select '$.rtrim(42)'::jsonpath;
+select '$.rtrim("x", "y")'::jsonpath;
+select '$.trim(42)'::jsonpath;
+select '$.trim("x", "y")'::jsonpath;
+
 select '$.time()'::jsonpath;
 select '$.time(6)'::jsonpath;
 select '$.time_tz()'::jsonpath;
-- 
2.51.0

From b3f966209a039c7ee69193f10cd2e3ca813b11da Mon Sep 17 00:00:00 2001
From: "David E. Wheeler" <david@justatheory.com>
Date: Mon, 2 Jun 2025 17:14:10 -0400
Subject: [PATCH v15 1/2] Rename jsonpath method arg tokens

Rename the `csv_` tokens to `int_`, because they represent signed or
unsigned integers, as follows:

*   `csv_elem` => `int_elem`
*   `csv_list` => `int_list`
*   `opt_csv_list` => `opt_int_list`

Rename the `datetime_precision` tokens to `uint_arg`, as they represent
unsigned integers and will be useful for other methods in the future, as
follows:

*   `datetime_precision` => `uint_elem`
*   `opt_datetime_precision` => `opt_uint_arg`

Rename the `datetime_template` tokens to `str_arg`, as they represent
strings and will be useful for other methods in the future, as follows:

*   `datetime_template` => `str_elem`
*   `opt_datetime_template` => `opt_str_arg`
---
 src/backend/utils/adt/jsonpath_gram.y | 42 +++++++++++++--------------
 1 file changed, 21 insertions(+), 21 deletions(-)

diff --git a/src/backend/utils/adt/jsonpath_gram.y b/src/backend/utils/adt/jsonpath_gram.y
index 499745a8fef..0b16cec18c4 100644
--- a/src/backend/utils/adt/jsonpath_gram.y
+++ b/src/backend/utils/adt/jsonpath_gram.y
@@ -92,10 +92,10 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 %type	<value>		scalar_value path_primary expr array_accessor
 					any_path accessor_op key predicate delimited_predicate
 					index_elem starts_with_initial expr_or_predicate
-					datetime_template opt_datetime_template csv_elem
-					datetime_precision opt_datetime_precision
+					str_elem opt_str_arg int_elem
+					uint_elem opt_uint_arg
 
-%type	<elems>		accessor_expr csv_list opt_csv_list
+%type	<elems>		accessor_expr int_list opt_int_list
 
 %type	<indexs>	index_list
 
@@ -254,7 +254,7 @@ accessor_op:
 	| '.' any_path					{ $$ = $2; }
 	| '.' method '(' ')'			{ $$ = makeItemType($2); }
 	| '?' '(' predicate ')'			{ $$ = makeItemUnary(jpiFilter, $3); }
-	| '.' DECIMAL_P '(' opt_csv_list ')'
+	| '.' DECIMAL_P '(' opt_int_list ')'
 		{
 			if (list_length($4) == 0)
 				$$ = makeItemBinary(jpiDecimal, NULL, NULL);
@@ -268,19 +268,19 @@ accessor_op:
 						 errmsg("invalid input syntax for type %s", "jsonpath"),
 						 errdetail(".decimal() can only have an optional precision[,scale].")));
 		}
-	| '.' DATETIME_P '(' opt_datetime_template ')'
+	| '.' DATETIME_P '(' opt_str_arg ')'
 		{ $$ = makeItemUnary(jpiDatetime, $4); }
-	| '.' TIME_P '(' opt_datetime_precision ')'
+	| '.' TIME_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTime, $4); }
-	| '.' TIME_TZ_P '(' opt_datetime_precision ')'
+	| '.' TIME_TZ_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimeTz, $4); }
-	| '.' TIMESTAMP_P '(' opt_datetime_precision ')'
+	| '.' TIMESTAMP_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimestamp, $4); }
-	| '.' TIMESTAMP_TZ_P '(' opt_datetime_precision ')'
+	| '.' TIMESTAMP_TZ_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimestampTz, $4); }
 	;
 
-csv_elem:
+int_elem:
 	INT_P
 		{ $$ = makeItemNumeric(&$1); }
 	| '+' INT_P %prec UMINUS
@@ -289,31 +289,31 @@ csv_elem:
 		{ $$ = makeItemUnary(jpiMinus, makeItemNumeric(&$2)); }
 	;
 
-csv_list:
-	csv_elem						{ $$ = list_make1($1); }
-	| csv_list ',' csv_elem			{ $$ = lappend($1, $3); }
+int_list:
+	int_elem						{ $$ = list_make1($1); }
+	| int_list ',' int_elem			{ $$ = lappend($1, $3); }
 	;
 
-opt_csv_list:
-	csv_list						{ $$ = $1; }
+opt_int_list:
+	int_list						{ $$ = $1; }
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
-datetime_precision:
+uint_elem:
 	INT_P							{ $$ = makeItemNumeric(&$1); }
 	;
 
-opt_datetime_precision:
-	datetime_precision				{ $$ = $1; }
+opt_uint_arg:
+	uint_elem						{ $$ = $1; }
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
-datetime_template:
+str_elem:
 	STRING_P						{ $$ = makeItemString(&$1); }
 	;
 
-opt_datetime_template:
-	datetime_template				{ $$ = $1; }
+opt_str_arg:
+	str_elem						{ $$ = $1; }
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
-- 
2.51.0

From 9c9dcdb69494a65cec73f600d1ad9979f403ead7 Mon Sep 17 00:00:00 2001
From: Florents Tselai <florents.tselai@gmail.com>
Date: Sun, 30 Nov 2025 16:12:58 -0500
Subject: [PATCH v15 2/2] Add additional jsonpath string methods

Add the following jsonpath methods:

*   l/r/btrim()
*   lower(), upper()
*   initcap()
*   replace()
*   split_part()

Each simply dispatches to the standard string processing functions.
These depend on the locale, but since it's set at `initdb`, they can be
considered immutable and therefore allowed in any jsonpath expression.
---
 doc/src/sgml/func/func-json.sgml             | 140 +++++++
 src/backend/utils/adt/jsonpath.c             | 117 +++++-
 src/backend/utils/adt/jsonpath_exec.c        | 209 ++++++++++
 src/backend/utils/adt/jsonpath_gram.y        |  28 +-
 src/backend/utils/adt/jsonpath_scan.l        |   8 +
 src/include/utils/jsonpath.h                 |   8 +
 src/test/regress/expected/jsonb_jsonpath.out | 399 +++++++++++++++++++
 src/test/regress/expected/jsonpath.out       | 137 +++++++
 src/test/regress/sql/jsonb_jsonpath.sql      | 109 +++++
 src/test/regress/sql/jsonpath.sql            |  31 ++
 10 files changed, 1181 insertions(+), 5 deletions(-)

diff --git a/doc/src/sgml/func/func-json.sgml b/doc/src/sgml/func/func-json.sgml
index 1ec73cff464..c2fa06bceff 100644
--- a/doc/src/sgml/func/func-json.sgml
+++ b/doc/src/sgml/func/func-json.sgml
@@ -2781,6 +2781,146 @@ ERROR:  jsonpath member accessor can only be applied to an object
         <returnvalue>[{"id": 0, "key": "x", "value": "20"}, {"id": 0, "key": "y", "value": 32}]</returnvalue>
        </para></entry>
       </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>lower()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String converted to all lower case according to the rules of the database's locale.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"TOM"', '$.lower()')</literal>
+        <returnvalue>"tom"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>upper()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String converted to all upper case according to the rules of the database's locale.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"tom"', '$.upper()')</literal>
+        <returnvalue>"TOM"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>initcap()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the first letter of each word converted to upper case
+        according to the rules of the database's locale. Words are sequences
+        of alphanumeric characters separated by non-alphanumeric characters.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"hi THOMAS"', '$.initcap()')</literal>
+        <returnvalue>"Hi Thomas"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>replace(<replaceable>from</replaceable>, <replaceable>to</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with all occurrences of substring from replaced with substring to.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"abcdefabcdef"', '$.replace("cd", "XX")')</literal>
+        <returnvalue>"abXXefabXXef"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>split_part(<replaceable>delimiter</replaceable>, <replaceable>n</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String split at occurrences of <replaceable>delimiter</replaceable>
+        and returns the <replaceable>n</replaceable>'th field (counting from
+        one) or, when <replaceable>n</replaceable> is negative, returns the
+        |<replaceable>n</replaceable>|'th-from-last field.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)')</literal>
+        <returnvalue>"def"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"abc,def,ghi,jkl"', '$.split_part(",", 2)')</literal>
+        <returnvalue>"ghi"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>ltrim(<replaceable>characters</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the longest string containing only spaces or the
+        characters in <replaceable>characters</replaceable> removed from the
+        start of <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal> jsonb_path_query('"  hello"', '$.ltrim()')</literal>
+        <returnvalue>"hello"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"zzzytest"', '$.ltrim("xyz")')</literal>
+        <returnvalue>"test"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>rtrim([ <replaceable>characters</replaceable> ])</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the longest string containing only spaces or the
+        characters in <replaceable>characters</replaceable> removed from the
+        end of <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"hello  "', '$.rtrim()')</literal>
+        <returnvalue>"hello"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"testxxzx"', '$.rtrim("xyz")')</literal>
+        <returnvalue>"test"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>btrim([ <replaceable>characters</replaceable> ])</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the longest string containing only spaces or the
+        characters in <replaceable>characters</replaceable> removed from the
+        start and end of <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"  hello  "', '$.btrim()')</literal>
+        <returnvalue>"hello"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"xyxtrimyyx"', '$.btrim("xyz")')</literal>
+        <returnvalue>"trim"</returnvalue>
+       </para></entry>
+      </row>
+
      </tbody>
     </tgroup>
    </table>
diff --git a/src/backend/utils/adt/jsonpath.c b/src/backend/utils/adt/jsonpath.c
index 762f7e8a09d..47f23503532 100644
--- a/src/backend/utils/adt/jsonpath.c
+++ b/src/backend/utils/adt/jsonpath.c
@@ -298,6 +298,8 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 		case jpiMod:
 		case jpiStartsWith:
 		case jpiDecimal:
+		case jpiStrReplace:
+		case jpiStrSplitPart:
 			{
 				/*
 				 * First, reserve place for left/right arg's positions, then
@@ -362,6 +364,9 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 		case jpiTimeTz:
 		case jpiTimestamp:
 		case jpiTimestampTz:
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
 			{
 				int32		arg = reserveSpaceForItemPointer(buf);
 
@@ -457,6 +462,9 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 		case jpiInteger:
 		case jpiNumber:
 		case jpiStringFunc:
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrInitcap:
 			break;
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", item->type);
@@ -831,6 +839,60 @@ printJsonPathItem(StringInfo buf, JsonPathItem *v, bool inKey,
 			}
 			appendStringInfoChar(buf, ')');
 			break;
+		case jpiStrReplace:
+			appendStringInfoString(buf, ".replace(");
+			jspGetLeftArg(v, &elem);
+			printJsonPathItem(buf, &elem, false, false);
+			appendStringInfoChar(buf, ',');
+			jspGetRightArg(v, &elem);
+			printJsonPathItem(buf, &elem, false, false);
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrLower:
+			appendStringInfoString(buf, ".lower()");
+			break;
+		case jpiStrUpper:
+			appendStringInfoString(buf, ".upper()");
+			break;
+		case jpiStrSplitPart:
+			appendStringInfoString(buf, ".split_part(");
+			jspGetLeftArg(v, &elem);
+			printJsonPathItem(buf, &elem, false, false);
+			appendStringInfoChar(buf, ',');
+			jspGetRightArg(v, &elem);
+			printJsonPathItem(buf, &elem, false, false);
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrLtrim:
+			appendStringInfoString(buf, ".ltrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrRtrim:
+			appendStringInfoString(buf, ".rtrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrBtrim:
+			appendStringInfoString(buf, ".btrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrInitcap:
+			appendStringInfoString(buf, ".initcap()");
+			break;
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", v->type);
 	}
@@ -914,6 +976,22 @@ jspOperationName(JsonPathItemType type)
 			return "timestamp";
 		case jpiTimestampTz:
 			return "timestamp_tz";
+		case jpiStrReplace:
+			return "replace";
+		case jpiStrLower:
+			return "lower";
+		case jpiStrUpper:
+			return "upper";
+		case jpiStrLtrim:
+			return "ltrim";
+		case jpiStrRtrim:
+			return "rtrim";
+		case jpiStrBtrim:
+			return "btrim";
+		case jpiStrInitcap:
+			return "initcap";
+		case jpiStrSplitPart:
+			return "split_part";
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", type);
 			return NULL;
@@ -1016,6 +1094,9 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 		case jpiInteger:
 		case jpiNumber:
 		case jpiStringFunc:
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrInitcap:
 			break;
 		case jpiString:
 		case jpiKey:
@@ -1041,6 +1122,8 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 		case jpiMod:
 		case jpiStartsWith:
 		case jpiDecimal:
+		case jpiStrReplace:
+		case jpiStrSplitPart:
 			read_int32(v->content.args.left, base, pos);
 			read_int32(v->content.args.right, base, pos);
 			break;
@@ -1055,6 +1138,9 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 		case jpiTimeTz:
 		case jpiTimestamp:
 		case jpiTimestampTz:
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
 			read_int32(v->content.arg, base, pos);
 			break;
 		case jpiIndexArray:
@@ -1090,7 +1176,10 @@ jspGetArg(JsonPathItem *v, JsonPathItem *a)
 		   v->type == jpiTime ||
 		   v->type == jpiTimeTz ||
 		   v->type == jpiTimestamp ||
-		   v->type == jpiTimestampTz);
+		   v->type == jpiTimestampTz ||
+		   v->type == jpiStrLtrim ||
+		   v->type == jpiStrRtrim ||
+		   v->type == jpiStrBtrim);
 
 	jspInitByBuffer(a, v->base, v->content.arg);
 }
@@ -1152,7 +1241,15 @@ jspGetNext(JsonPathItem *v, JsonPathItem *a)
 			   v->type == jpiTime ||
 			   v->type == jpiTimeTz ||
 			   v->type == jpiTimestamp ||
-			   v->type == jpiTimestampTz);
+			   v->type == jpiTimestampTz ||
+			   v->type == jpiStrReplace ||
+			   v->type == jpiStrLower ||
+			   v->type == jpiStrUpper ||
+			   v->type == jpiStrLtrim ||
+			   v->type == jpiStrRtrim ||
+			   v->type == jpiStrBtrim ||
+			   v->type == jpiStrInitcap ||
+			   v->type == jpiStrSplitPart);
 
 		if (a)
 			jspInitByBuffer(a, v->base, v->nextPos);
@@ -1179,7 +1276,9 @@ jspGetLeftArg(JsonPathItem *v, JsonPathItem *a)
 		   v->type == jpiDiv ||
 		   v->type == jpiMod ||
 		   v->type == jpiStartsWith ||
-		   v->type == jpiDecimal);
+		   v->type == jpiDecimal ||
+		   v->type == jpiStrReplace ||
+		   v->type == jpiStrSplitPart);
 
 	jspInitByBuffer(a, v->base, v->content.args.left);
 }
@@ -1201,7 +1300,9 @@ jspGetRightArg(JsonPathItem *v, JsonPathItem *a)
 		   v->type == jpiDiv ||
 		   v->type == jpiMod ||
 		   v->type == jpiStartsWith ||
-		   v->type == jpiDecimal);
+		   v->type == jpiDecimal ||
+		   v->type == jpiStrReplace ||
+		   v->type == jpiStrSplitPart);
 
 	jspInitByBuffer(a, v->base, v->content.args.right);
 }
@@ -1501,6 +1602,14 @@ jspIsMutableWalker(JsonPathItem *jpi, struct JsonPathMutableContext *cxt)
 			case jpiInteger:
 			case jpiNumber:
 			case jpiStringFunc:
+			case jpiStrReplace:
+			case jpiStrLower:
+			case jpiStrUpper:
+			case jpiStrLtrim:
+			case jpiStrRtrim:
+			case jpiStrBtrim:
+			case jpiStrInitcap:
+			case jpiStrSplitPart:
 				status = jpdsNonDateTime;
 				break;
 
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 8156695e97e..efc4b1375ef 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -302,6 +302,8 @@ static JsonPathExecResult executeNumericItemMethod(JsonPathExecContext *cxt,
 												   JsonValueList *found);
 static JsonPathExecResult executeDateTimeMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
 												JsonbValue *jb, JsonValueList *found);
+static JsonPathExecResult executeStringInternalMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
+													  JsonbValue *jb, JsonValueList *found);
 static JsonPathExecResult executeKeyValueMethod(JsonPathExecContext *cxt,
 												JsonPathItem *jsp, JsonbValue *jb, JsonValueList *found);
 static JsonPathExecResult appendBoolResult(JsonPathExecContext *cxt,
@@ -1661,6 +1663,23 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
 			}
 			break;
 
+		case jpiStrReplace:
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
+		case jpiStrInitcap:
+		case jpiStrSplitPart:
+			{
+				if (unwrap && JsonbType(jb) == jbvArray)
+					return executeItemUnwrapTargetArray(cxt, jsp, jb, found, false);
+
+				return executeStringInternalMethod(cxt, jsp, jb, found);
+			}
+			break;
+
+
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", jsp->type);
 	}
@@ -2794,6 +2813,196 @@ executeDateTimeMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
 	return executeNextItem(cxt, jsp, &elem, jb, found, hasNext);
 }
 
+/*
+ * Implementation of .upper(), lower() et. al. methods,
+ * that forward their actual implementation to internal functions.
+ */
+static JsonPathExecResult
+executeStringInternalMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
+							JsonbValue *jb, JsonValueList *found)
+{
+	JsonbValue	jbvbuf;
+	bool		hasNext;
+	JsonPathExecResult res = jperNotFound;
+	JsonPathItem elem;
+	Datum		str;			/* Datum representation for the current string
+								 * value. The first argument to internal
+								 * functions */
+	char	   *tmp = NULL;
+	char	   *resStr = NULL;
+
+	Assert(jsp->type == jpiStrReplace ||
+		   jsp->type == jpiStrLower ||
+		   jsp->type == jpiStrUpper ||
+		   jsp->type == jpiStrLtrim ||
+		   jsp->type == jpiStrRtrim ||
+		   jsp->type == jpiStrBtrim ||
+		   jsp->type == jpiStrInitcap ||
+		   jsp->type == jpiStrSplitPart);
+
+	if (!(jb = getScalar(jb, jbvString)))
+		RETURN_ERROR(ereport(ERROR,
+							 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+							  errmsg("jsonpath item method .%s() can only be applied to a string",
+									 jspOperationName(jsp->type)))));
+
+	tmp = pnstrdup(jb->val.string.val, jb->val.string.len);
+	str = CStringGetTextDatum(tmp);
+
+	/* Internal string functions that accept no arguments */
+	switch (jsp->type)
+	{
+		case jpiStrReplace:
+			{
+				char	   *from_str,
+						   *to_str;
+				int			from_len,
+							to_len;
+
+				jspGetLeftArg(jsp, &elem);
+				if (elem.type != jpiString)
+					elog(ERROR, "invalid jsonpath item type for .replace() from");
+
+				from_str = jspGetString(&elem, &from_len);
+
+				jspGetRightArg(jsp, &elem);
+				if (elem.type != jpiString)
+					elog(ERROR, "invalid jsonpath item type for .replace() to");
+
+				to_str = jspGetString(&elem, &to_len);
+
+				resStr = TextDatumGetCString(DirectFunctionCall3Coll(replace_text,
+																	 DEFAULT_COLLATION_OID,
+																	 CStringGetTextDatum(tmp),
+																	 CStringGetTextDatum(from_str),
+																	 CStringGetTextDatum(to_str)));
+				break;
+			}
+		case jpiStrLower:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(lower, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiStrUpper:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(upper, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
+			{
+				char	   *characters_str;
+				int			characters_len;
+				PGFunction	func = NULL;
+
+				if (jsp->content.arg)
+				{
+					switch (jsp->type)
+					{
+						case jpiStrLtrim:
+							func = ltrim;
+							break;
+						case jpiStrRtrim:
+							func = rtrim;
+							break;
+						case jpiStrBtrim:
+							func = btrim;
+							break;
+						default:;
+					}
+					jspGetArg(jsp, &elem);
+					if (elem.type != jpiString)
+						elog(ERROR, "invalid jsonpath item type for .%s() argument", jspOperationName(jsp->type));
+
+					characters_str = jspGetString(&elem, &characters_len);
+					resStr = TextDatumGetCString(DirectFunctionCall2Coll(func,
+																		 DEFAULT_COLLATION_OID, str,
+																		 CStringGetTextDatum(characters_str)));
+					break;
+				}
+
+				switch (jsp->type)
+				{
+					case jpiStrLtrim:
+						func = ltrim1;
+						break;
+					case jpiStrRtrim:
+						func = rtrim1;
+						break;
+					case jpiStrBtrim:
+						func = btrim1;
+						break;
+					default:;
+				}
+				resStr = TextDatumGetCString(DirectFunctionCall1Coll(func,
+																	 DEFAULT_COLLATION_OID, str));
+				break;
+			}
+
+		case jpiStrInitcap:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(initcap, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiStrSplitPart:
+			{
+				char	   *from_str;
+				Numeric		n;
+				int			from_len;
+
+				jspGetLeftArg(jsp, &elem);
+				if (elem.type != jpiString)
+					elog(ERROR, "invalid jsonpath item type for .split_part()");
+
+				from_str = jspGetString(&elem, &from_len);
+
+				jspGetRightArg(jsp, &elem);
+				if (elem.type != jpiNumeric)
+					elog(ERROR, "invalid jsonpath item type for .split_part()");
+
+				n = jspGetNumeric(&elem);
+
+				resStr = TextDatumGetCString(DirectFunctionCall3Coll(split_part,
+																	 C_COLLATION_OID,
+																	 CStringGetTextDatum(tmp),
+																	 CStringGetTextDatum(from_str),
+																	 DirectFunctionCall1(numeric_int4, NumericGetDatum(n))));
+				break;
+			}
+		default:
+			elog(ERROR, "unsupported jsonpath item type: %d", jsp->type);
+	}
+
+	if (resStr)
+		res = jperOk;
+
+	hasNext = jspGetNext(jsp, &elem);
+
+	if (!hasNext && !found)
+		return res;
+
+	jb = hasNext ? &jbvbuf : palloc(sizeof(*jb));
+
+	/* Create the appropriate jb value to return */
+	switch (jsp->type)
+	{
+			/* Cases for functions that return text */
+		case jpiStrReplace:
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
+		case jpiStrInitcap:
+		case jpiStrSplitPart:
+			jb->type = jbvString;
+			jb->val.string.val = resStr;
+			jb->val.string.len = strlen(jb->val.string.val);
+			break;
+		default:
+			;
+			/* do nothing */
+			Assert(false);
+	}
+
+	return executeNextItem(cxt, jsp, &elem, jb, found, hasNext);
+}
+
 /*
  * Implementation of .keyvalue() method.
  *
diff --git a/src/backend/utils/adt/jsonpath_gram.y b/src/backend/utils/adt/jsonpath_gram.y
index 0b16cec18c4..53bf779e152 100644
--- a/src/backend/utils/adt/jsonpath_gram.y
+++ b/src/backend/utils/adt/jsonpath_gram.y
@@ -86,6 +86,8 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 %token	<str>		DATETIME_P
 %token	<str>		BIGINT_P BOOLEAN_P DATE_P DECIMAL_P INTEGER_P NUMBER_P
 %token	<str>		STRINGFUNC_P TIME_P TIME_TZ_P TIMESTAMP_P TIMESTAMP_TZ_P
+%token	<str>		STR_REPLACE_P STR_LOWER_P STR_UPPER_P STR_LTRIM_P STR_RTRIM_P STR_BTRIM_P
+					STR_INITCAP_P STR_SPLIT_PART_P
 
 %type	<result>	result
 
@@ -95,7 +97,7 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 					str_elem opt_str_arg int_elem
 					uint_elem opt_uint_arg
 
-%type	<elems>		accessor_expr int_list opt_int_list
+%type	<elems>		accessor_expr int_list opt_int_list str_int_args str_str_args
 
 %type	<indexs>	index_list
 
@@ -278,6 +280,16 @@ accessor_op:
 		{ $$ = makeItemUnary(jpiTimestamp, $4); }
 	| '.' TIMESTAMP_TZ_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimestampTz, $4); }
+	| '.' STR_REPLACE_P '(' str_str_args ')'
+		{ $$ = makeItemBinary(jpiStrReplace, linitial($4), lsecond($4)); }
+	| '.' STR_SPLIT_PART_P '(' str_int_args ')'
+		{ $$ = makeItemBinary(jpiStrSplitPart, linitial($4), lsecond($4)); }
+	| '.' STR_LTRIM_P '(' opt_str_arg ')'
+		{ $$ = makeItemUnary(jpiStrLtrim, $4); }
+	| '.' STR_RTRIM_P '(' opt_str_arg ')'
+		{ $$ = makeItemUnary(jpiStrRtrim, $4); }
+	| '.' STR_BTRIM_P '(' opt_str_arg ')'
+		{ $$ = makeItemUnary(jpiStrBtrim, $4); }
 	;
 
 int_elem:
@@ -317,6 +329,14 @@ opt_str_arg:
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
+str_int_args:
+	str_elem ',' int_elem			{ $$ = list_make2($1, $3); }
+	;
+
+str_str_args:
+	str_elem ',' str_elem 			{ $$ = list_make2($1, $3); }
+	;
+
 key:
 	key_name						{ $$ = makeItemKey(&$1); }
 	;
@@ -357,6 +377,9 @@ key_name:
 	| TIME_TZ_P
 	| TIMESTAMP_P
 	| TIMESTAMP_TZ_P
+	| STR_LTRIM_P
+	| STR_RTRIM_P
+	| STR_BTRIM_P
 	;
 
 method:
@@ -373,6 +396,9 @@ method:
 	| INTEGER_P						{ $$ = jpiInteger; }
 	| NUMBER_P						{ $$ = jpiNumber; }
 	| STRINGFUNC_P					{ $$ = jpiStringFunc; }
+	| STR_LOWER_P					{ $$ = jpiStrLower; }
+	| STR_UPPER_P					{ $$ = jpiStrUpper; }
+	| STR_INITCAP_P					{ $$ = jpiStrInitcap; }
 	;
 %%
 
diff --git a/src/backend/utils/adt/jsonpath_scan.l b/src/backend/utils/adt/jsonpath_scan.l
index 8c3a0a9c642..0c3e77cf2e5 100644
--- a/src/backend/utils/adt/jsonpath_scan.l
+++ b/src/backend/utils/adt/jsonpath_scan.l
@@ -413,8 +413,13 @@ static const JsonPathKeyword keywords[] = {
 	{4, true, TRUE_P, "true"},
 	{4, false, TYPE_P, "type"},
 	{4, false, WITH_P, "with"},
+	{5, false, STR_BTRIM_P, "btrim"},
 	{5, true, FALSE_P, "false"},
 	{5, false, FLOOR_P, "floor"},
+	{5, false, STR_LOWER_P, "lower"},
+	{5, false, STR_LTRIM_P, "ltrim"},
+	{5, false, STR_RTRIM_P, "rtrim"},
+	{5, false, STR_UPPER_P, "upper"},
 	{6, false, BIGINT_P, "bigint"},
 	{6, false, DOUBLE_P, "double"},
 	{6, false, EXISTS_P, "exists"},
@@ -425,13 +430,16 @@ static const JsonPathKeyword keywords[] = {
 	{7, false, BOOLEAN_P, "boolean"},
 	{7, false, CEILING_P, "ceiling"},
 	{7, false, DECIMAL_P, "decimal"},
+	{7, false, STR_INITCAP_P, "initcap"},
 	{7, false, INTEGER_P, "integer"},
+	{7, false, STR_REPLACE_P, "replace"},
 	{7, false, TIME_TZ_P, "time_tz"},
 	{7, false, UNKNOWN_P, "unknown"},
 	{8, false, DATETIME_P, "datetime"},
 	{8, false, KEYVALUE_P, "keyvalue"},
 	{9, false, TIMESTAMP_P, "timestamp"},
 	{10, false, LIKE_REGEX_P, "like_regex"},
+	{10,false, STR_SPLIT_PART_P, "split_part"},
 	{12, false, TIMESTAMP_TZ_P, "timestamp_tz"},
 };
 
diff --git a/src/include/utils/jsonpath.h b/src/include/utils/jsonpath.h
index 23a76d233e9..2d0c53f7b06 100644
--- a/src/include/utils/jsonpath.h
+++ b/src/include/utils/jsonpath.h
@@ -115,6 +115,14 @@ typedef enum JsonPathItemType
 	jpiTimeTz,					/* .time_tz() item method */
 	jpiTimestamp,				/* .timestamp() item method */
 	jpiTimestampTz,				/* .timestamp_tz() item method */
+	jpiStrReplace,				/* .replace() item method */
+	jpiStrLower,				/* .lower() item method */
+	jpiStrUpper,				/* .upper() item method */
+	jpiStrLtrim,				/* .ltrim() item method */
+	jpiStrRtrim,				/* .rtrim() item method */
+	jpiStrBtrim,				/* .btrim() item method */
+	jpiStrInitcap,				/* .initcap() item method */
+	jpiStrSplitPart,			/* .split_part() item method */
 } JsonPathItemType;
 
 /* XQuery regex mode flags for LIKE_REGEX predicate */
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e91a29..cea539717f9 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -2723,6 +2723,405 @@ select jsonb_path_query('"2023-08-15 12:34:56"', '$.timestamp().string()');
 (1 row)
 
 rollback;
+-- test .ltrim()
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"zzzytest"', '$.ltrim("xyz")');
+ jsonb_path_query 
+------------------
+ "test"
+(1 row)
+
+select jsonb_path_query('null', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('null', '$.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.ltrim()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('{}', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('true', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('1234', '$.ltrim().type()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim()');
+  jsonb_path_query_array  
+--------------------------
+ ["maybe  ", "yes", "no"]
+(1 row)
+
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .rtrim()
+select jsonb_path_query('"   hello   "', '$.rtrim(" ")');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+select jsonb_path_query('"testxxzx"', '$.rtrim("xyz")');
+ jsonb_path_query 
+------------------
+ "test"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+-- test .btrim()
+select jsonb_path_query('"   hello   "', '$.btrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+select jsonb_path_query('"xyxtrimyyx"', '$.btrim("xyz")');
+ jsonb_path_query 
+------------------
+ "trim"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.btrim()');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.btrim()');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+-- test .lower()
+select jsonb_path_query('null', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('null', '$.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.lower()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('{}', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.lower()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.lower()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('true', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('1234', '$.lower().type()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower()');
+ jsonb_path_query_array 
+------------------------
+ ["maybe", "yes", "no"]
+(1 row)
+
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .upper()
+select jsonb_path_query('null', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('null', '$.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.upper()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('{}', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.upper()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.upper()');
+ jsonb_path_query 
+------------------
+ "1.23AAA"
+(1 row)
+
+select jsonb_path_query('1234', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('true', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('1234', '$.upper().type()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper()');
+ jsonb_path_query_array 
+------------------------
+ ["MAYBE", "YES", "NO"]
+(1 row)
+
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .initcap()
+select jsonb_path_query('null', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('null', '$.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.initcap()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('{}', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('true', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('1234', '$.initcap().type()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('["maybe yes", "probably no"]', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "Maybe Yes"
+ "Probably No"
+(2 rows)
+
+-- Test .replace()
+select jsonb_path_query('null', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('null', '$.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('["x", "y", "z"]', '$.replace("x", "bye")');
+ jsonb_path_query 
+------------------
+ "bye"
+ "y"
+ "z"
+(3 rows)
+
+select jsonb_path_query('{}', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('"hello world"', '$.replace("hello","bye")');
+ jsonb_path_query 
+------------------
+ "bye world"
+(1 row)
+
+select jsonb_path_query('"hello world"', '$.replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
+-- Test .split_part()
+select jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)');
+ jsonb_path_query 
+------------------
+ "def"
+(1 row)
+
+select jsonb_path_query('"abc,def,ghi,jkl"', '$.split_part(",", -2)');
+ jsonb_path_query 
+------------------
+ "ghi"
+(1 row)
+
+-- Test string methods play nicely together
+select jsonb_path_query('"hello world"', '$.replace("hello","bye").upper()');
+ jsonb_path_query 
+------------------
+ "BYE WORLD"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye")');
+ jsonb_path_query 
+------------------
+ "bye world"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.upper().lower().upper().replace("HELLO", "BYE")');
+ jsonb_path_query 
+------------------
+ "BYE WORLD"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
+select jsonb_path_query('"   hElLo WorlD "', '$.btrim().lower().upper().lower().replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
 -- Test .time()
 select jsonb_path_query('null', '$.time()');
 ERROR:  jsonpath item method .time() can only be applied to a string
diff --git a/src/test/regress/expected/jsonpath.out b/src/test/regress/expected/jsonpath.out
index fd9bd755f52..a13022feabd 100644
--- a/src/test/regress/expected/jsonpath.out
+++ b/src/test/regress/expected/jsonpath.out
@@ -435,6 +435,143 @@ select '$.string()'::jsonpath;
  $.string()
 (1 row)
 
+select '$.replace("hello","bye")'::jsonpath;
+         jsonpath         
+--------------------------
+ $.replace("hello","bye")
+(1 row)
+
+select '$.lower()'::jsonpath;
+ jsonpath  
+-----------
+ $.lower()
+(1 row)
+
+select '$.upper()'::jsonpath;
+ jsonpath  
+-----------
+ $.upper()
+(1 row)
+
+select '$.lower().upper().lower().replace("hello","bye")'::jsonpath;
+                     jsonpath                     
+--------------------------------------------------
+ $.lower().upper().lower().replace("hello","bye")
+(1 row)
+
+select '$.ltrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.ltrim()
+(1 row)
+
+select '$.ltrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.ltrim("xyz")
+(1 row)
+
+select '$.rtrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.rtrim()
+(1 row)
+
+select '$.rtrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.rtrim("xyz")
+(1 row)
+
+select '$.btrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.btrim()
+(1 row)
+
+select '$.btrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.btrim("xyz")
+(1 row)
+
+select '$.initcap()'::jsonpath;
+  jsonpath   
+-------------
+ $.initcap()
+(1 row)
+
+select '$.split_part("~@~", 2)'::jsonpath;
+       jsonpath        
+-----------------------
+ $.split_part("~@~",2)
+(1 row)
+
+-- Parse errors
+select '$.replace("hello")'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.replace("hello")'::jsonpath;
+               ^
+select '$.replace()'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.replace()'::jsonpath;
+               ^
+select '$.replace("hello","bye","extra")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.replace("hello","bye","extra")'::jsonpath;
+               ^
+select '$.split_part("~@~")'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.split_part("~@~")'::jsonpath;
+               ^
+select '$.split_part()'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.split_part()'::jsonpath;
+               ^
+select '$.split_part("~@~", "hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.split_part("~@~", "hi")'::jsonpath;
+               ^
+select '$.split_part("~@~", 2, "extra")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.split_part("~@~", 2, "extra")'::jsonpath;
+               ^
+select '$.lower("hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.lower("hi")'::jsonpath;
+               ^
+select '$.upper("hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.upper("hi")'::jsonpath;
+               ^
+select '$.initcap("hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.initcap("hi")'::jsonpath;
+               ^
+select '$.ltrim(42)'::jsonpath;
+ERROR:  syntax error at or near "42" of jsonpath input
+LINE 1: select '$.ltrim(42)'::jsonpath;
+               ^
+select '$.ltrim("x", "y")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.ltrim("x", "y")'::jsonpath;
+               ^
+select '$.rtrim(42)'::jsonpath;
+ERROR:  syntax error at or near "42" of jsonpath input
+LINE 1: select '$.rtrim(42)'::jsonpath;
+               ^
+select '$.rtrim("x", "y")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.rtrim("x", "y")'::jsonpath;
+               ^
+select '$.trim(42)'::jsonpath;
+ERROR:  syntax error at or near "(" of jsonpath input
+LINE 1: select '$.trim(42)'::jsonpath;
+               ^
+select '$.trim("x", "y")'::jsonpath;
+ERROR:  syntax error at or near "(" of jsonpath input
+LINE 1: select '$.trim("x", "y")'::jsonpath;
+               ^
 select '$.time()'::jsonpath;
  jsonpath 
 ----------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a5269..8169719343e 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -623,6 +623,115 @@ select jsonb_path_query('"2023-08-15 12:34:56 +5:30"', '$.timestamp_tz().string(
 select jsonb_path_query('"2023-08-15 12:34:56"', '$.timestamp().string()');
 rollback;
 
+-- test .ltrim()
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+select jsonb_path_query('"   hello   "', '$.ltrim()');
+select jsonb_path_query('"zzzytest"', '$.ltrim("xyz")');
+select jsonb_path_query('null', '$.ltrim()');
+select jsonb_path_query('null', '$.ltrim()', silent => true);
+select jsonb_path_query('[]', '$.ltrim()');
+select jsonb_path_query('[]', 'strict $.ltrim()');
+select jsonb_path_query('{}', '$.ltrim()');
+select jsonb_path_query('[]', 'strict $.ltrim()', silent => true);
+select jsonb_path_query('{}', '$.ltrim()', silent => true);
+select jsonb_path_query('1.23', '$.ltrim()');
+select jsonb_path_query('"1.23"', '$.ltrim()');
+select jsonb_path_query('"1.23aaa"', '$.ltrim()');
+select jsonb_path_query('1234', '$.ltrim()');
+select jsonb_path_query('true', '$.ltrim()');
+select jsonb_path_query('1234', '$.ltrim().type()');
+select jsonb_path_query('[2, true]', '$.ltrim()');
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim()');
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim().type()');
+
+-- test .rtrim()
+select jsonb_path_query('"   hello   "', '$.rtrim(" ")');
+select jsonb_path_query('"testxxzx"', '$.rtrim("xyz")');
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+
+-- test .btrim()
+select jsonb_path_query('"   hello   "', '$.btrim(" ")');
+select jsonb_path_query('"xyxtrimyyx"', '$.btrim("xyz")');
+select jsonb_path_query('"   hello   "', '$.btrim()');
+select jsonb_path_query('"   hello   "', '$.btrim()');
+
+-- test .lower()
+select jsonb_path_query('null', '$.lower()');
+select jsonb_path_query('null', '$.lower()', silent => true);
+select jsonb_path_query('[]', '$.lower()');
+select jsonb_path_query('[]', 'strict $.lower()');
+select jsonb_path_query('{}', '$.lower()');
+select jsonb_path_query('[]', 'strict $.lower()', silent => true);
+select jsonb_path_query('{}', '$.lower()', silent => true);
+select jsonb_path_query('1.23', '$.lower()');
+select jsonb_path_query('"1.23"', '$.lower()');
+select jsonb_path_query('"1.23aaa"', '$.lower()');
+select jsonb_path_query('1234', '$.lower()');
+select jsonb_path_query('true', '$.lower()');
+select jsonb_path_query('1234', '$.lower().type()');
+select jsonb_path_query('[2, true]', '$.lower()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower().type()');
+
+-- test .upper()
+select jsonb_path_query('null', '$.upper()');
+select jsonb_path_query('null', '$.upper()', silent => true);
+select jsonb_path_query('[]', '$.upper()');
+select jsonb_path_query('[]', 'strict $.upper()');
+select jsonb_path_query('{}', '$.upper()');
+select jsonb_path_query('[]', 'strict $.upper()', silent => true);
+select jsonb_path_query('{}', '$.upper()', silent => true);
+select jsonb_path_query('1.23', '$.upper()');
+select jsonb_path_query('"1.23"', '$.upper()');
+select jsonb_path_query('"1.23aaa"', '$.upper()');
+select jsonb_path_query('1234', '$.upper()');
+select jsonb_path_query('true', '$.upper()');
+select jsonb_path_query('1234', '$.upper().type()');
+select jsonb_path_query('[2, true]', '$.upper()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper().type()');
+
+-- test .initcap()
+select jsonb_path_query('null', '$.initcap()');
+select jsonb_path_query('null', '$.initcap()', silent => true);
+select jsonb_path_query('[]', '$.initcap()');
+select jsonb_path_query('[]', 'strict $.initcap()');
+select jsonb_path_query('{}', '$.initcap()');
+select jsonb_path_query('[]', 'strict $.initcap()', silent => true);
+select jsonb_path_query('{}', '$.initcap()', silent => true);
+select jsonb_path_query('1.23', '$.initcap()');
+select jsonb_path_query('"1.23"', '$.initcap()');
+select jsonb_path_query('"1.23aaa"', '$.initcap()');
+select jsonb_path_query('1234', '$.initcap()');
+select jsonb_path_query('true', '$.initcap()');
+select jsonb_path_query('1234', '$.initcap().type()');
+select jsonb_path_query('[2, true]', '$.initcap()');
+select jsonb_path_query('["maybe yes", "probably no"]', '$.initcap()');
+
+-- Test .replace()
+select jsonb_path_query('null', '$.replace("x", "bye")');
+select jsonb_path_query('null', '$.replace("x", "bye")', silent => true);
+select jsonb_path_query('["x", "y", "z"]', '$.replace("x", "bye")');
+select jsonb_path_query('{}', '$.replace("x", "bye")');
+select jsonb_path_query('[]', 'strict $.replace("x", "bye")', silent => true);
+select jsonb_path_query('{}', '$.replace("x", "bye")', silent => true);
+select jsonb_path_query('1.23', '$.replace("x", "bye")');
+select jsonb_path_query('"hello world"', '$.replace("hello","bye")');
+select jsonb_path_query('"hello world"', '$.replace("hello","bye") starts with "bye"');
+
+-- Test .split_part()
+select jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)');
+select jsonb_path_query('"abc,def,ghi,jkl"', '$.split_part(",", -2)');
+
+-- Test string methods play nicely together
+select jsonb_path_query('"hello world"', '$.replace("hello","bye").upper()');
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye")');
+select jsonb_path_query('"hElLo WorlD"', '$.upper().lower().upper().replace("HELLO", "BYE")');
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye") starts with "bye"');
+select jsonb_path_query('"   hElLo WorlD "', '$.btrim().lower().upper().lower().replace("hello","bye") starts with "bye"');
+
 -- Test .time()
 select jsonb_path_query('null', '$.time()');
 select jsonb_path_query('true', '$.time()');
diff --git a/src/test/regress/sql/jsonpath.sql b/src/test/regress/sql/jsonpath.sql
index 61a5270d4e8..7dd2e57e7a6 100644
--- a/src/test/regress/sql/jsonpath.sql
+++ b/src/test/regress/sql/jsonpath.sql
@@ -78,6 +78,37 @@ select '$.boolean()'::jsonpath;
 select '$.date()'::jsonpath;
 select '$.decimal(4,2)'::jsonpath;
 select '$.string()'::jsonpath;
+select '$.replace("hello","bye")'::jsonpath;
+select '$.lower()'::jsonpath;
+select '$.upper()'::jsonpath;
+select '$.lower().upper().lower().replace("hello","bye")'::jsonpath;
+select '$.ltrim()'::jsonpath;
+select '$.ltrim("xyz")'::jsonpath;
+select '$.rtrim()'::jsonpath;
+select '$.rtrim("xyz")'::jsonpath;
+select '$.btrim()'::jsonpath;
+select '$.btrim("xyz")'::jsonpath;
+select '$.initcap()'::jsonpath;
+select '$.split_part("~@~", 2)'::jsonpath;
+
+-- Parse errors
+select '$.replace("hello")'::jsonpath;
+select '$.replace()'::jsonpath;
+select '$.replace("hello","bye","extra")'::jsonpath;
+select '$.split_part("~@~")'::jsonpath;
+select '$.split_part()'::jsonpath;
+select '$.split_part("~@~", "hi")'::jsonpath;
+select '$.split_part("~@~", 2, "extra")'::jsonpath;
+select '$.lower("hi")'::jsonpath;
+select '$.upper("hi")'::jsonpath;
+select '$.initcap("hi")'::jsonpath;
+select '$.ltrim(42)'::jsonpath;
+select '$.ltrim("x", "y")'::jsonpath;
+select '$.rtrim(42)'::jsonpath;
+select '$.rtrim("x", "y")'::jsonpath;
+select '$.trim(42)'::jsonpath;
+select '$.trim("x", "y")'::jsonpath;
+
 select '$.time()'::jsonpath;
 select '$.time(6)'::jsonpath;
 select '$.time_tz()'::jsonpath;
-- 
2.51.0

From 2f25c8723be53cbe7d576407f6b010df31bebbc7 Mon Sep 17 00:00:00 2001
From: "David E. Wheeler" <david@justatheory.com>
Date: Mon, 2 Jun 2025 17:14:10 -0400
Subject: [PATCH v16 1/2] Rename jsonpath method arg tokens

Rename the `csv_` tokens to `int_`, because they represent signed or
unsigned integers, as follows:

*   `csv_elem` => `int_elem`
*   `csv_list` => `int_list`
*   `opt_csv_list` => `opt_int_list`

Rename the `datetime_precision` tokens to `uint_arg`, as they represent
unsigned integers and will be useful for other methods in the future, as
follows:

*   `datetime_precision` => `uint_elem`
*   `opt_datetime_precision` => `opt_uint_arg`

Rename the `datetime_template` tokens to `str_arg`, as they represent
strings and will be useful for other methods in the future, as follows:

*   `datetime_template` => `str_elem`
*   `opt_datetime_template` => `opt_str_arg`
---
 src/backend/utils/adt/jsonpath_gram.y | 42 +++++++++++++--------------
 1 file changed, 21 insertions(+), 21 deletions(-)

diff --git a/src/backend/utils/adt/jsonpath_gram.y b/src/backend/utils/adt/jsonpath_gram.y
index 4543626ffc8..8ec4ca33212 100644
--- a/src/backend/utils/adt/jsonpath_gram.y
+++ b/src/backend/utils/adt/jsonpath_gram.y
@@ -92,10 +92,10 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 %type	<value>		scalar_value path_primary expr array_accessor
 					any_path accessor_op key predicate delimited_predicate
 					index_elem starts_with_initial expr_or_predicate
-					datetime_template opt_datetime_template csv_elem
-					datetime_precision opt_datetime_precision
+					str_elem opt_str_arg int_elem
+					uint_elem opt_uint_arg
 
-%type	<elems>		accessor_expr csv_list opt_csv_list
+%type	<elems>		accessor_expr int_list opt_int_list
 
 %type	<indexs>	index_list
 
@@ -254,7 +254,7 @@ accessor_op:
 	| '.' any_path					{ $$ = $2; }
 	| '.' method '(' ')'			{ $$ = makeItemType($2); }
 	| '?' '(' predicate ')'			{ $$ = makeItemUnary(jpiFilter, $3); }
-	| '.' DECIMAL_P '(' opt_csv_list ')'
+	| '.' DECIMAL_P '(' opt_int_list ')'
 		{
 			if (list_length($4) == 0)
 				$$ = makeItemBinary(jpiDecimal, NULL, NULL);
@@ -268,19 +268,19 @@ accessor_op:
 						 errmsg("invalid input syntax for type %s", "jsonpath"),
 						 errdetail(".decimal() can only have an optional precision[,scale].")));
 		}
-	| '.' DATETIME_P '(' opt_datetime_template ')'
+	| '.' DATETIME_P '(' opt_str_arg ')'
 		{ $$ = makeItemUnary(jpiDatetime, $4); }
-	| '.' TIME_P '(' opt_datetime_precision ')'
+	| '.' TIME_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTime, $4); }
-	| '.' TIME_TZ_P '(' opt_datetime_precision ')'
+	| '.' TIME_TZ_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimeTz, $4); }
-	| '.' TIMESTAMP_P '(' opt_datetime_precision ')'
+	| '.' TIMESTAMP_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimestamp, $4); }
-	| '.' TIMESTAMP_TZ_P '(' opt_datetime_precision ')'
+	| '.' TIMESTAMP_TZ_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimestampTz, $4); }
 	;
 
-csv_elem:
+int_elem:
 	INT_P
 		{ $$ = makeItemNumeric(&$1); }
 	| '+' INT_P %prec UMINUS
@@ -289,31 +289,31 @@ csv_elem:
 		{ $$ = makeItemUnary(jpiMinus, makeItemNumeric(&$2)); }
 	;
 
-csv_list:
-	csv_elem						{ $$ = list_make1($1); }
-	| csv_list ',' csv_elem			{ $$ = lappend($1, $3); }
+int_list:
+	int_elem						{ $$ = list_make1($1); }
+	| int_list ',' int_elem			{ $$ = lappend($1, $3); }
 	;
 
-opt_csv_list:
-	csv_list						{ $$ = $1; }
+opt_int_list:
+	int_list						{ $$ = $1; }
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
-datetime_precision:
+uint_elem:
 	INT_P							{ $$ = makeItemNumeric(&$1); }
 	;
 
-opt_datetime_precision:
-	datetime_precision				{ $$ = $1; }
+opt_uint_arg:
+	uint_elem						{ $$ = $1; }
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
-datetime_template:
+str_elem:
 	STRING_P						{ $$ = makeItemString(&$1); }
 	;
 
-opt_datetime_template:
-	datetime_template				{ $$ = $1; }
+opt_str_arg:
+	str_elem						{ $$ = $1; }
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
-- 
2.51.0

From fbc9017d57182c396c5bbac9917502f7dbb6906e Mon Sep 17 00:00:00 2001
From: Florents Tselai <florents.tselai@gmail.com>
Date: Sun, 4 Jan 2026 15:49:04 -0500
Subject: [PATCH v16 2/2] Add additional jsonpath string methods

Add the following jsonpath methods:

*   l/r/btrim()
*   lower(), upper()
*   initcap()
*   replace()
*   split_part()

Each simply dispatches to the standard string processing functions.
These depend on the locale, but since it's set at `initdb`, they can be
considered immutable and therefore allowed in any jsonpath expression.
---
 doc/src/sgml/func/func-json.sgml              | 140 ++++++
 src/backend/utils/adt/jsonpath.c              | 117 ++++-
 src/backend/utils/adt/jsonpath_exec.c         | 207 +++++++++
 src/backend/utils/adt/jsonpath_gram.y         |  28 +-
 src/backend/utils/adt/jsonpath_scan.l         |   8 +
 src/include/utils/jsonpath.h                  |   8 +
 src/test/regress/expected/jsonb_jsonpath.out  | 399 ++++++++++++++++++
 src/test/regress/expected/jsonpath.out        | 137 ++++++
 .../regress/expected/sqljson_queryfuncs.out   |  10 +-
 src/test/regress/sql/jsonb_jsonpath.sql       | 109 +++++
 src/test/regress/sql/jsonpath.sql             |  31 ++
 src/test/regress/sql/sqljson_queryfuncs.sql   |  11 +-
 12 files changed, 1198 insertions(+), 7 deletions(-)

diff --git a/doc/src/sgml/func/func-json.sgml b/doc/src/sgml/func/func-json.sgml
index 1ec73cff464..86c308454a8 100644
--- a/doc/src/sgml/func/func-json.sgml
+++ b/doc/src/sgml/func/func-json.sgml
@@ -2781,6 +2781,146 @@ ERROR:  jsonpath member accessor can only be applied to an object
         <returnvalue>[{"id": 0, "key": "x", "value": "20"}, {"id": 0, "key": "y", "value": 32}]</returnvalue>
        </para></entry>
       </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>lower()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String converted to all lower case according to the rules of the database's locale.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"TOM"', '$.lower()')</literal>
+        <returnvalue>"tom"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>upper()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String converted to all upper case according to the rules of the database's locale.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"tom"', '$.upper()')</literal>
+        <returnvalue>"TOM"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>initcap()</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the first letter of each word converted to upper case
+        according to the rules of the database's locale. Words are sequences
+        of alphanumeric characters separated by non-alphanumeric characters.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"hi THOMAS"', '$.initcap()')</literal>
+        <returnvalue>"Hi Thomas"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>replace(<replaceable>from</replaceable>, <replaceable>to</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with all occurrences of substring from replaced with substring to.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"abcdefabcdef"', '$.replace("cd", "XX")')</literal>
+        <returnvalue>"abXXefabXXef"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>split_part(<replaceable>delimiter</replaceable>, <replaceable>n</replaceable>)</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String split at occurrences of <replaceable>delimiter</replaceable>
+        and returns the <replaceable>n</replaceable>'th field (counting from
+        one) or, when <replaceable>n</replaceable> is negative, returns the
+        |<replaceable>n</replaceable>|'th-from-last field.
+       </para>
+       <para>
+        <literal>jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)')</literal>
+        <returnvalue>"def"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"abc,def,ghi,jkl"', '$.split_part(",", 3)')</literal>
+        <returnvalue>"ghi"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>ltrim([ <replaceable>characters</replaceable> ])</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the longest string containing only spaces or the
+        characters in <replaceable>characters</replaceable> removed from the
+        start of <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal> jsonb_path_query('"  hello"', '$.ltrim()')</literal>
+        <returnvalue>"hello"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"zzzytest"', '$.ltrim("xyz")')</literal>
+        <returnvalue>"test"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>rtrim([ <replaceable>characters</replaceable> ])</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the longest string containing only spaces or the
+        characters in <replaceable>characters</replaceable> removed from the
+        end of <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"hello  "', '$.rtrim()')</literal>
+        <returnvalue>"hello"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"testxxzx"', '$.rtrim("xyz")')</literal>
+        <returnvalue>"test"</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <replaceable>string</replaceable> <literal>.</literal> <literal>btrim([ <replaceable>characters</replaceable> ])</literal>
+        <returnvalue><replaceable>string</replaceable></returnvalue>
+       </para>
+       <para>
+        String with the longest string containing only spaces or the
+        characters in <replaceable>characters</replaceable> removed from the
+        start and end of <replaceable>string</replaceable>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"  hello  "', '$.btrim()')</literal>
+        <returnvalue>"hello"</returnvalue>
+       </para>
+       <para>
+        <literal>jsonb_path_query('"xyxtrimyyx"', '$.btrim("xyz")')</literal>
+        <returnvalue>"trim"</returnvalue>
+       </para></entry>
+      </row>
+
      </tbody>
     </tgroup>
    </table>
diff --git a/src/backend/utils/adt/jsonpath.c b/src/backend/utils/adt/jsonpath.c
index 18a8046d6cf..756479d626d 100644
--- a/src/backend/utils/adt/jsonpath.c
+++ b/src/backend/utils/adt/jsonpath.c
@@ -298,6 +298,8 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 		case jpiMod:
 		case jpiStartsWith:
 		case jpiDecimal:
+		case jpiStrReplace:
+		case jpiStrSplitPart:
 			{
 				/*
 				 * First, reserve place for left/right arg's positions, then
@@ -362,6 +364,9 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 		case jpiTimeTz:
 		case jpiTimestamp:
 		case jpiTimestampTz:
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
 			{
 				int32		arg = reserveSpaceForItemPointer(buf);
 
@@ -457,6 +462,9 @@ flattenJsonPathParseItem(StringInfo buf, int *result, struct Node *escontext,
 		case jpiInteger:
 		case jpiNumber:
 		case jpiStringFunc:
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrInitcap:
 			break;
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", item->type);
@@ -831,6 +839,60 @@ printJsonPathItem(StringInfo buf, JsonPathItem *v, bool inKey,
 			}
 			appendStringInfoChar(buf, ')');
 			break;
+		case jpiStrReplace:
+			appendStringInfoString(buf, ".replace(");
+			jspGetLeftArg(v, &elem);
+			printJsonPathItem(buf, &elem, false, false);
+			appendStringInfoChar(buf, ',');
+			jspGetRightArg(v, &elem);
+			printJsonPathItem(buf, &elem, false, false);
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrLower:
+			appendStringInfoString(buf, ".lower()");
+			break;
+		case jpiStrUpper:
+			appendStringInfoString(buf, ".upper()");
+			break;
+		case jpiStrSplitPart:
+			appendStringInfoString(buf, ".split_part(");
+			jspGetLeftArg(v, &elem);
+			printJsonPathItem(buf, &elem, false, false);
+			appendStringInfoChar(buf, ',');
+			jspGetRightArg(v, &elem);
+			printJsonPathItem(buf, &elem, false, false);
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrLtrim:
+			appendStringInfoString(buf, ".ltrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrRtrim:
+			appendStringInfoString(buf, ".rtrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrBtrim:
+			appendStringInfoString(buf, ".btrim(");
+			if (v->content.arg)
+			{
+				jspGetArg(v, &elem);
+				printJsonPathItem(buf, &elem, false, false);
+			}
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiStrInitcap:
+			appendStringInfoString(buf, ".initcap()");
+			break;
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", v->type);
 	}
@@ -914,6 +976,22 @@ jspOperationName(JsonPathItemType type)
 			return "timestamp";
 		case jpiTimestampTz:
 			return "timestamp_tz";
+		case jpiStrReplace:
+			return "replace";
+		case jpiStrLower:
+			return "lower";
+		case jpiStrUpper:
+			return "upper";
+		case jpiStrLtrim:
+			return "ltrim";
+		case jpiStrRtrim:
+			return "rtrim";
+		case jpiStrBtrim:
+			return "btrim";
+		case jpiStrInitcap:
+			return "initcap";
+		case jpiStrSplitPart:
+			return "split_part";
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", type);
 			return NULL;
@@ -1016,6 +1094,9 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 		case jpiInteger:
 		case jpiNumber:
 		case jpiStringFunc:
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrInitcap:
 			break;
 		case jpiString:
 		case jpiKey:
@@ -1041,6 +1122,8 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 		case jpiMod:
 		case jpiStartsWith:
 		case jpiDecimal:
+		case jpiStrReplace:
+		case jpiStrSplitPart:
 			read_int32(v->content.args.left, base, pos);
 			read_int32(v->content.args.right, base, pos);
 			break;
@@ -1055,6 +1138,9 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 		case jpiTimeTz:
 		case jpiTimestamp:
 		case jpiTimestampTz:
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
 			read_int32(v->content.arg, base, pos);
 			break;
 		case jpiIndexArray:
@@ -1090,7 +1176,10 @@ jspGetArg(JsonPathItem *v, JsonPathItem *a)
 		   v->type == jpiTime ||
 		   v->type == jpiTimeTz ||
 		   v->type == jpiTimestamp ||
-		   v->type == jpiTimestampTz);
+		   v->type == jpiTimestampTz ||
+		   v->type == jpiStrLtrim ||
+		   v->type == jpiStrRtrim ||
+		   v->type == jpiStrBtrim);
 
 	jspInitByBuffer(a, v->base, v->content.arg);
 }
@@ -1152,7 +1241,15 @@ jspGetNext(JsonPathItem *v, JsonPathItem *a)
 			   v->type == jpiTime ||
 			   v->type == jpiTimeTz ||
 			   v->type == jpiTimestamp ||
-			   v->type == jpiTimestampTz);
+			   v->type == jpiTimestampTz ||
+			   v->type == jpiStrReplace ||
+			   v->type == jpiStrLower ||
+			   v->type == jpiStrUpper ||
+			   v->type == jpiStrLtrim ||
+			   v->type == jpiStrRtrim ||
+			   v->type == jpiStrBtrim ||
+			   v->type == jpiStrInitcap ||
+			   v->type == jpiStrSplitPart);
 
 		if (a)
 			jspInitByBuffer(a, v->base, v->nextPos);
@@ -1179,7 +1276,9 @@ jspGetLeftArg(JsonPathItem *v, JsonPathItem *a)
 		   v->type == jpiDiv ||
 		   v->type == jpiMod ||
 		   v->type == jpiStartsWith ||
-		   v->type == jpiDecimal);
+		   v->type == jpiDecimal ||
+		   v->type == jpiStrReplace ||
+		   v->type == jpiStrSplitPart);
 
 	jspInitByBuffer(a, v->base, v->content.args.left);
 }
@@ -1201,7 +1300,9 @@ jspGetRightArg(JsonPathItem *v, JsonPathItem *a)
 		   v->type == jpiDiv ||
 		   v->type == jpiMod ||
 		   v->type == jpiStartsWith ||
-		   v->type == jpiDecimal);
+		   v->type == jpiDecimal ||
+		   v->type == jpiStrReplace ||
+		   v->type == jpiStrSplitPart);
 
 	jspInitByBuffer(a, v->base, v->content.args.right);
 }
@@ -1501,6 +1602,14 @@ jspIsMutableWalker(JsonPathItem *jpi, struct JsonPathMutableContext *cxt)
 			case jpiInteger:
 			case jpiNumber:
 			case jpiStringFunc:
+			case jpiStrReplace:
+			case jpiStrLower:
+			case jpiStrUpper:
+			case jpiStrLtrim:
+			case jpiStrRtrim:
+			case jpiStrBtrim:
+			case jpiStrInitcap:
+			case jpiStrSplitPart:
 				status = jpdsNonDateTime;
 				break;
 
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 52ae0ba4cf7..1d5d35f677d 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -302,6 +302,8 @@ static JsonPathExecResult executeNumericItemMethod(JsonPathExecContext *cxt,
 												   JsonValueList *found);
 static JsonPathExecResult executeDateTimeMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
 												JsonbValue *jb, JsonValueList *found);
+static JsonPathExecResult executeStringInternalMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
+													  JsonbValue *jb, JsonValueList *found);
 static JsonPathExecResult executeKeyValueMethod(JsonPathExecContext *cxt,
 												JsonPathItem *jsp, JsonbValue *jb, JsonValueList *found);
 static JsonPathExecResult appendBoolResult(JsonPathExecContext *cxt,
@@ -1661,6 +1663,23 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
 			}
 			break;
 
+		case jpiStrReplace:
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
+		case jpiStrInitcap:
+		case jpiStrSplitPart:
+			{
+				if (unwrap && JsonbType(jb) == jbvArray)
+					return executeItemUnwrapTargetArray(cxt, jsp, jb, found, false);
+
+				return executeStringInternalMethod(cxt, jsp, jb, found);
+			}
+			break;
+
+
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", jsp->type);
 	}
@@ -2794,6 +2813,194 @@ executeDateTimeMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
 	return executeNextItem(cxt, jsp, &elem, jb, found, hasNext);
 }
 
+/*
+ * Implementation of .upper(), lower() et. al. methods,
+ * that forward their actual implementation to internal functions.
+ */
+static JsonPathExecResult
+executeStringInternalMethod(JsonPathExecContext *cxt, JsonPathItem *jsp,
+							JsonbValue *jb, JsonValueList *found)
+{
+	JsonbValue	jbvbuf;
+	bool		hasNext;
+	JsonPathExecResult res = jperNotFound;
+	JsonPathItem elem;
+	Datum		str;			/* Datum representation for the current string
+								 * value. The first argument to internal
+								 * functions */
+	char	   *resStr;
+
+	Assert(jsp->type == jpiStrReplace ||
+		   jsp->type == jpiStrLower ||
+		   jsp->type == jpiStrUpper ||
+		   jsp->type == jpiStrLtrim ||
+		   jsp->type == jpiStrRtrim ||
+		   jsp->type == jpiStrBtrim ||
+		   jsp->type == jpiStrInitcap ||
+		   jsp->type == jpiStrSplitPart);
+
+	if (!(jb = getScalar(jb, jbvString)))
+		RETURN_ERROR(ereport(ERROR,
+							 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+							  errmsg("jsonpath item method .%s() can only be applied to a string",
+									 jspOperationName(jsp->type)))));
+
+	str = PointerGetDatum(cstring_to_text_with_len(jb->val.string.val, jb->val.string.len));
+
+	/* Internal string functions that accept no arguments */
+	switch (jsp->type)
+	{
+		case jpiStrReplace:
+			{
+				char	   *from_str,
+						   *to_str;
+				int			from_len,
+							to_len;
+
+				jspGetLeftArg(jsp, &elem);
+				if (elem.type != jpiString)
+					elog(ERROR, "invalid jsonpath item type for .replace() from");
+
+				from_str = jspGetString(&elem, &from_len);
+
+				jspGetRightArg(jsp, &elem);
+				if (elem.type != jpiString)
+					elog(ERROR, "invalid jsonpath item type for .replace() to");
+
+				to_str = jspGetString(&elem, &to_len);
+
+				resStr = TextDatumGetCString(DirectFunctionCall3Coll(replace_text,
+																	 DEFAULT_COLLATION_OID,
+																	 str,
+																	 CStringGetTextDatum(from_str),
+																	 CStringGetTextDatum(to_str)));
+				break;
+			}
+		case jpiStrLower:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(lower, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiStrUpper:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(upper, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
+			{
+				char	   *characters_str;
+				int			characters_len;
+				PGFunction	func = NULL;
+
+				if (jsp->content.arg)
+				{
+					switch (jsp->type)
+					{
+						case jpiStrLtrim:
+							func = ltrim;
+							break;
+						case jpiStrRtrim:
+							func = rtrim;
+							break;
+						case jpiStrBtrim:
+							func = btrim;
+							break;
+						default:;
+					}
+					jspGetArg(jsp, &elem);
+					if (elem.type != jpiString)
+						elog(ERROR, "invalid jsonpath item type for .%s() argument", jspOperationName(jsp->type));
+
+					characters_str = jspGetString(&elem, &characters_len);
+					resStr = TextDatumGetCString(DirectFunctionCall2Coll(func,
+																		 DEFAULT_COLLATION_OID, str,
+																		 CStringGetTextDatum(characters_str)));
+					break;
+				}
+
+				switch (jsp->type)
+				{
+					case jpiStrLtrim:
+						func = ltrim1;
+						break;
+					case jpiStrRtrim:
+						func = rtrim1;
+						break;
+					case jpiStrBtrim:
+						func = btrim1;
+						break;
+					default:;
+				}
+				resStr = TextDatumGetCString(DirectFunctionCall1Coll(func,
+																	 DEFAULT_COLLATION_OID, str));
+				break;
+			}
+
+		case jpiStrInitcap:
+			resStr = TextDatumGetCString(DirectFunctionCall1Coll(initcap, DEFAULT_COLLATION_OID, str));
+			break;
+		case jpiStrSplitPart:
+			{
+				char	   *from_str;
+				Numeric		n;
+				int			from_len;
+
+				jspGetLeftArg(jsp, &elem);
+				if (elem.type != jpiString)
+					elog(ERROR, "invalid jsonpath item type for .split_part()");
+
+				from_str = jspGetString(&elem, &from_len);
+
+				jspGetRightArg(jsp, &elem);
+				if (elem.type != jpiNumeric)
+					elog(ERROR, "invalid jsonpath item type for .split_part()");
+
+				n = jspGetNumeric(&elem);
+
+				resStr = TextDatumGetCString(DirectFunctionCall3Coll(split_part,
+																	 DEFAULT_COLLATION_OID,
+																	 str,
+																	 CStringGetTextDatum(from_str),
+																	 DirectFunctionCall1(numeric_int4, NumericGetDatum(n))));
+				break;
+			}
+		default:
+			elog(ERROR, "unsupported jsonpath item type: %d", jsp->type);
+	}
+
+	if (resStr)
+		res = jperOk;
+
+	hasNext = jspGetNext(jsp, &elem);
+
+	if (!hasNext && !found)
+		return res;
+
+	jb = hasNext ? &jbvbuf : palloc(sizeof(*jb));
+
+	/* Create the appropriate jb value to return */
+	switch (jsp->type)
+	{
+			/* Cases for functions that return text */
+		case jpiStrReplace:
+		case jpiStrLower:
+		case jpiStrUpper:
+		case jpiStrLtrim:
+		case jpiStrRtrim:
+		case jpiStrBtrim:
+		case jpiStrInitcap:
+		case jpiStrSplitPart:
+			jb->type = jbvString;
+			jb->val.string.val = resStr;
+			jb->val.string.len = strlen(jb->val.string.val);
+			break;
+		default:
+			;
+			/* do nothing */
+			Assert(false);
+	}
+
+	return executeNextItem(cxt, jsp, &elem, jb, found, hasNext);
+}
+
 /*
  * Implementation of .keyvalue() method.
  *
diff --git a/src/backend/utils/adt/jsonpath_gram.y b/src/backend/utils/adt/jsonpath_gram.y
index 8ec4ca33212..c077d64d2f5 100644
--- a/src/backend/utils/adt/jsonpath_gram.y
+++ b/src/backend/utils/adt/jsonpath_gram.y
@@ -86,6 +86,8 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 %token	<str>		DATETIME_P
 %token	<str>		BIGINT_P BOOLEAN_P DATE_P DECIMAL_P INTEGER_P NUMBER_P
 %token	<str>		STRINGFUNC_P TIME_P TIME_TZ_P TIMESTAMP_P TIMESTAMP_TZ_P
+%token	<str>		STR_REPLACE_P STR_LOWER_P STR_UPPER_P STR_LTRIM_P STR_RTRIM_P STR_BTRIM_P
+					STR_INITCAP_P STR_SPLIT_PART_P
 
 %type	<result>	result
 
@@ -95,7 +97,7 @@ static bool makeItemLikeRegex(JsonPathParseItem *expr,
 					str_elem opt_str_arg int_elem
 					uint_elem opt_uint_arg
 
-%type	<elems>		accessor_expr int_list opt_int_list
+%type	<elems>		accessor_expr int_list opt_int_list str_int_args str_str_args
 
 %type	<indexs>	index_list
 
@@ -278,6 +280,16 @@ accessor_op:
 		{ $$ = makeItemUnary(jpiTimestamp, $4); }
 	| '.' TIMESTAMP_TZ_P '(' opt_uint_arg ')'
 		{ $$ = makeItemUnary(jpiTimestampTz, $4); }
+	| '.' STR_REPLACE_P '(' str_str_args ')'
+		{ $$ = makeItemBinary(jpiStrReplace, linitial($4), lsecond($4)); }
+	| '.' STR_SPLIT_PART_P '(' str_int_args ')'
+		{ $$ = makeItemBinary(jpiStrSplitPart, linitial($4), lsecond($4)); }
+	| '.' STR_LTRIM_P '(' opt_str_arg ')'
+		{ $$ = makeItemUnary(jpiStrLtrim, $4); }
+	| '.' STR_RTRIM_P '(' opt_str_arg ')'
+		{ $$ = makeItemUnary(jpiStrRtrim, $4); }
+	| '.' STR_BTRIM_P '(' opt_str_arg ')'
+		{ $$ = makeItemUnary(jpiStrBtrim, $4); }
 	;
 
 int_elem:
@@ -317,6 +329,14 @@ opt_str_arg:
 	| /* EMPTY */					{ $$ = NULL; }
 	;
 
+str_int_args:
+	str_elem ',' int_elem			{ $$ = list_make2($1, $3); }
+	;
+
+str_str_args:
+	str_elem ',' str_elem 			{ $$ = list_make2($1, $3); }
+	;
+
 key:
 	key_name						{ $$ = makeItemKey(&$1); }
 	;
@@ -357,6 +377,9 @@ key_name:
 	| TIME_TZ_P
 	| TIMESTAMP_P
 	| TIMESTAMP_TZ_P
+	| STR_LTRIM_P
+	| STR_RTRIM_P
+	| STR_BTRIM_P
 	;
 
 method:
@@ -373,6 +396,9 @@ method:
 	| INTEGER_P						{ $$ = jpiInteger; }
 	| NUMBER_P						{ $$ = jpiNumber; }
 	| STRINGFUNC_P					{ $$ = jpiStringFunc; }
+	| STR_LOWER_P					{ $$ = jpiStrLower; }
+	| STR_UPPER_P					{ $$ = jpiStrUpper; }
+	| STR_INITCAP_P					{ $$ = jpiStrInitcap; }
 	;
 %%
 
diff --git a/src/backend/utils/adt/jsonpath_scan.l b/src/backend/utils/adt/jsonpath_scan.l
index 38c5841e879..9fa8e9eb92a 100644
--- a/src/backend/utils/adt/jsonpath_scan.l
+++ b/src/backend/utils/adt/jsonpath_scan.l
@@ -413,8 +413,13 @@ static const JsonPathKeyword keywords[] = {
 	{4, true, TRUE_P, "true"},
 	{4, false, TYPE_P, "type"},
 	{4, false, WITH_P, "with"},
+	{5, false, STR_BTRIM_P, "btrim"},
 	{5, true, FALSE_P, "false"},
 	{5, false, FLOOR_P, "floor"},
+	{5, false, STR_LOWER_P, "lower"},
+	{5, false, STR_LTRIM_P, "ltrim"},
+	{5, false, STR_RTRIM_P, "rtrim"},
+	{5, false, STR_UPPER_P, "upper"},
 	{6, false, BIGINT_P, "bigint"},
 	{6, false, DOUBLE_P, "double"},
 	{6, false, EXISTS_P, "exists"},
@@ -425,13 +430,16 @@ static const JsonPathKeyword keywords[] = {
 	{7, false, BOOLEAN_P, "boolean"},
 	{7, false, CEILING_P, "ceiling"},
 	{7, false, DECIMAL_P, "decimal"},
+	{7, false, STR_INITCAP_P, "initcap"},
 	{7, false, INTEGER_P, "integer"},
+	{7, false, STR_REPLACE_P, "replace"},
 	{7, false, TIME_TZ_P, "time_tz"},
 	{7, false, UNKNOWN_P, "unknown"},
 	{8, false, DATETIME_P, "datetime"},
 	{8, false, KEYVALUE_P, "keyvalue"},
 	{9, false, TIMESTAMP_P, "timestamp"},
 	{10, false, LIKE_REGEX_P, "like_regex"},
+	{10,false, STR_SPLIT_PART_P, "split_part"},
 	{12, false, TIMESTAMP_TZ_P, "timestamp_tz"},
 };
 
diff --git a/src/include/utils/jsonpath.h b/src/include/utils/jsonpath.h
index 6f529d74dcd..8d27206e242 100644
--- a/src/include/utils/jsonpath.h
+++ b/src/include/utils/jsonpath.h
@@ -115,6 +115,14 @@ typedef enum JsonPathItemType
 	jpiTimeTz,					/* .time_tz() item method */
 	jpiTimestamp,				/* .timestamp() item method */
 	jpiTimestampTz,				/* .timestamp_tz() item method */
+	jpiStrReplace,				/* .replace() item method */
+	jpiStrLower,				/* .lower() item method */
+	jpiStrUpper,				/* .upper() item method */
+	jpiStrLtrim,				/* .ltrim() item method */
+	jpiStrRtrim,				/* .rtrim() item method */
+	jpiStrBtrim,				/* .btrim() item method */
+	jpiStrInitcap,				/* .initcap() item method */
+	jpiStrSplitPart,			/* .split_part() item method */
 } JsonPathItemType;
 
 /* XQuery regex mode flags for LIKE_REGEX predicate */
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e91a29..cea539717f9 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -2723,6 +2723,405 @@ select jsonb_path_query('"2023-08-15 12:34:56"', '$.timestamp().string()');
 (1 row)
 
 rollback;
+-- test .ltrim()
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "hello   "
+(1 row)
+
+select jsonb_path_query('"zzzytest"', '$.ltrim("xyz")');
+ jsonb_path_query 
+------------------
+ "test"
+(1 row)
+
+select jsonb_path_query('null', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('null', '$.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.ltrim()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('{}', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.ltrim()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.ltrim()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('true', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('1234', '$.ltrim().type()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.ltrim()');
+ERROR:  jsonpath item method .ltrim() can only be applied to a string
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim()');
+  jsonb_path_query_array  
+--------------------------
+ ["maybe  ", "yes", "no"]
+(1 row)
+
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .rtrim()
+select jsonb_path_query('"   hello   "', '$.rtrim(" ")');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+select jsonb_path_query('"testxxzx"', '$.rtrim("xyz")');
+ jsonb_path_query 
+------------------
+ "test"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+ jsonb_path_query 
+------------------
+ "   hello"
+(1 row)
+
+-- test .btrim()
+select jsonb_path_query('"   hello   "', '$.btrim(" ")');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+select jsonb_path_query('"xyxtrimyyx"', '$.btrim("xyz")');
+ jsonb_path_query 
+------------------
+ "trim"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.btrim()');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+select jsonb_path_query('"   hello   "', '$.btrim()');
+ jsonb_path_query 
+------------------
+ "hello"
+(1 row)
+
+-- test .lower()
+select jsonb_path_query('null', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('null', '$.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.lower()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('{}', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.lower()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.lower()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.lower()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('true', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('1234', '$.lower().type()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.lower()');
+ERROR:  jsonpath item method .lower() can only be applied to a string
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower()');
+ jsonb_path_query_array 
+------------------------
+ ["maybe", "yes", "no"]
+(1 row)
+
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .upper()
+select jsonb_path_query('null', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('null', '$.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.upper()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('{}', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.upper()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.upper()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.upper()');
+ jsonb_path_query 
+------------------
+ "1.23AAA"
+(1 row)
+
+select jsonb_path_query('1234', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('true', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('1234', '$.upper().type()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.upper()');
+ERROR:  jsonpath item method .upper() can only be applied to a string
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper()');
+ jsonb_path_query_array 
+------------------------
+ ["MAYBE", "YES", "NO"]
+(1 row)
+
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper().type()');
+     jsonb_path_query_array     
+--------------------------------
+ ["string", "string", "string"]
+(1 row)
+
+-- test .initcap()
+select jsonb_path_query('null', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('null', '$.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', '$.initcap()');
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('[]', 'strict $.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('{}', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.initcap()', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('"1.23"', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "1.23"
+(1 row)
+
+select jsonb_path_query('"1.23aaa"', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "1.23aaa"
+(1 row)
+
+select jsonb_path_query('1234', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('true', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('1234', '$.initcap().type()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('[2, true]', '$.initcap()');
+ERROR:  jsonpath item method .initcap() can only be applied to a string
+select jsonb_path_query('["maybe yes", "probably no"]', '$.initcap()');
+ jsonb_path_query 
+------------------
+ "Maybe Yes"
+ "Probably No"
+(2 rows)
+
+-- Test .replace()
+select jsonb_path_query('null', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('null', '$.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('["x", "y", "z"]', '$.replace("x", "bye")');
+ jsonb_path_query 
+------------------
+ "bye"
+ "y"
+ "z"
+(3 rows)
+
+select jsonb_path_query('{}', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('[]', 'strict $.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('{}', '$.replace("x", "bye")', silent => true);
+ jsonb_path_query 
+------------------
+(0 rows)
+
+select jsonb_path_query('1.23', '$.replace("x", "bye")');
+ERROR:  jsonpath item method .replace() can only be applied to a string
+select jsonb_path_query('"hello world"', '$.replace("hello","bye")');
+ jsonb_path_query 
+------------------
+ "bye world"
+(1 row)
+
+select jsonb_path_query('"hello world"', '$.replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
+-- Test .split_part()
+select jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)');
+ jsonb_path_query 
+------------------
+ "def"
+(1 row)
+
+select jsonb_path_query('"abc,def,ghi,jkl"', '$.split_part(",", -2)');
+ jsonb_path_query 
+------------------
+ "ghi"
+(1 row)
+
+-- Test string methods play nicely together
+select jsonb_path_query('"hello world"', '$.replace("hello","bye").upper()');
+ jsonb_path_query 
+------------------
+ "BYE WORLD"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye")');
+ jsonb_path_query 
+------------------
+ "bye world"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.upper().lower().upper().replace("HELLO", "BYE")');
+ jsonb_path_query 
+------------------
+ "BYE WORLD"
+(1 row)
+
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
+select jsonb_path_query('"   hElLo WorlD "', '$.btrim().lower().upper().lower().replace("hello","bye") starts with "bye"');
+ jsonb_path_query 
+------------------
+ true
+(1 row)
+
 -- Test .time()
 select jsonb_path_query('null', '$.time()');
 ERROR:  jsonpath item method .time() can only be applied to a string
diff --git a/src/test/regress/expected/jsonpath.out b/src/test/regress/expected/jsonpath.out
index fd9bd755f52..a13022feabd 100644
--- a/src/test/regress/expected/jsonpath.out
+++ b/src/test/regress/expected/jsonpath.out
@@ -435,6 +435,143 @@ select '$.string()'::jsonpath;
  $.string()
 (1 row)
 
+select '$.replace("hello","bye")'::jsonpath;
+         jsonpath         
+--------------------------
+ $.replace("hello","bye")
+(1 row)
+
+select '$.lower()'::jsonpath;
+ jsonpath  
+-----------
+ $.lower()
+(1 row)
+
+select '$.upper()'::jsonpath;
+ jsonpath  
+-----------
+ $.upper()
+(1 row)
+
+select '$.lower().upper().lower().replace("hello","bye")'::jsonpath;
+                     jsonpath                     
+--------------------------------------------------
+ $.lower().upper().lower().replace("hello","bye")
+(1 row)
+
+select '$.ltrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.ltrim()
+(1 row)
+
+select '$.ltrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.ltrim("xyz")
+(1 row)
+
+select '$.rtrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.rtrim()
+(1 row)
+
+select '$.rtrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.rtrim("xyz")
+(1 row)
+
+select '$.btrim()'::jsonpath;
+ jsonpath  
+-----------
+ $.btrim()
+(1 row)
+
+select '$.btrim("xyz")'::jsonpath;
+    jsonpath    
+----------------
+ $.btrim("xyz")
+(1 row)
+
+select '$.initcap()'::jsonpath;
+  jsonpath   
+-------------
+ $.initcap()
+(1 row)
+
+select '$.split_part("~@~", 2)'::jsonpath;
+       jsonpath        
+-----------------------
+ $.split_part("~@~",2)
+(1 row)
+
+-- Parse errors
+select '$.replace("hello")'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.replace("hello")'::jsonpath;
+               ^
+select '$.replace()'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.replace()'::jsonpath;
+               ^
+select '$.replace("hello","bye","extra")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.replace("hello","bye","extra")'::jsonpath;
+               ^
+select '$.split_part("~@~")'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.split_part("~@~")'::jsonpath;
+               ^
+select '$.split_part()'::jsonpath;
+ERROR:  syntax error at or near ")" of jsonpath input
+LINE 1: select '$.split_part()'::jsonpath;
+               ^
+select '$.split_part("~@~", "hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.split_part("~@~", "hi")'::jsonpath;
+               ^
+select '$.split_part("~@~", 2, "extra")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.split_part("~@~", 2, "extra")'::jsonpath;
+               ^
+select '$.lower("hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.lower("hi")'::jsonpath;
+               ^
+select '$.upper("hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.upper("hi")'::jsonpath;
+               ^
+select '$.initcap("hi")'::jsonpath;
+ERROR:  syntax error at or near """ of jsonpath input
+LINE 1: select '$.initcap("hi")'::jsonpath;
+               ^
+select '$.ltrim(42)'::jsonpath;
+ERROR:  syntax error at or near "42" of jsonpath input
+LINE 1: select '$.ltrim(42)'::jsonpath;
+               ^
+select '$.ltrim("x", "y")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.ltrim("x", "y")'::jsonpath;
+               ^
+select '$.rtrim(42)'::jsonpath;
+ERROR:  syntax error at or near "42" of jsonpath input
+LINE 1: select '$.rtrim(42)'::jsonpath;
+               ^
+select '$.rtrim("x", "y")'::jsonpath;
+ERROR:  syntax error at or near "," of jsonpath input
+LINE 1: select '$.rtrim("x", "y")'::jsonpath;
+               ^
+select '$.trim(42)'::jsonpath;
+ERROR:  syntax error at or near "(" of jsonpath input
+LINE 1: select '$.trim(42)'::jsonpath;
+               ^
+select '$.trim("x", "y")'::jsonpath;
+ERROR:  syntax error at or near "(" of jsonpath input
+LINE 1: select '$.trim("x", "y")'::jsonpath;
+               ^
 select '$.time()'::jsonpath;
  jsonpath 
 ----------
diff --git a/src/test/regress/expected/sqljson_queryfuncs.out b/src/test/regress/expected/sqljson_queryfuncs.out
index 53145f50f18..3bcb436552a 100644
--- a/src/test/regress/expected/sqljson_queryfuncs.out
+++ b/src/test/regress/expected/sqljson_queryfuncs.out
@@ -1147,7 +1147,7 @@ INSERT INTO test_jsonb_constraints VALUES ('{"a": 10}', 1);
 ERROR:  new row for relation "test_jsonb_constraints" violates check constraint "test_jsonb_constraint4"
 DETAIL:  Failing row contains ({"a": 10}, 1, [1, 2]).
 DROP TABLE test_jsonb_constraints;
--- Test mutabilily of query functions
+-- Test mutability of query functions
 CREATE TABLE test_jsonb_mutability(js jsonb, b int);
 CREATE INDEX ON test_jsonb_mutability (JSON_QUERY(js, '$'));
 CREATE INDEX ON test_jsonb_mutability (JSON_QUERY(js, '$.a[0]'));
@@ -1216,6 +1216,14 @@ ERROR:  functions in index expression must be marked IMMUTABLE
 CREATE INDEX ON test_jsonb_mutability (JSON_QUERY(js, '$[1, $.a ? (@.datetime("HH:MI") == $x)]' PASSING '12:34'::time AS x));
 CREATE INDEX ON test_jsonb_mutability (JSON_VALUE(js, '$' DEFAULT random()::int ON ERROR));
 ERROR:  functions in index expression must be marked IMMUTABLE
+CREATE INDEX ON test_jsonb_mutability (JSON_QUERY(js, '$.rtrim()'));
+CREATE INDEX ON test_jsonb_mutability (JSON_QUERY(js, '$.ltrim()'));
+CREATE INDEX ON test_jsonb_mutability (JSON_QUERY(js, '$.btrim()'));
+CREATE INDEX ON test_jsonb_mutability (JSON_QUERY(js, '$.lower()'));
+CREATE INDEX ON test_jsonb_mutability (JSON_QUERY(js, '$.upper()'));
+CREATE INDEX ON test_jsonb_mutability (JSON_QUERY(js, '$.initcap()'));
+CREATE INDEX ON test_jsonb_mutability (JSON_QUERY(js, '$.replace("hello", "bye")'));
+CREATE INDEX ON test_jsonb_mutability (JSON_QUERY(js, '$.split_part(",", 2)'));
 -- DEFAULT expression
 CREATE OR REPLACE FUNCTION ret_setint() RETURNS SETOF integer AS
 $$
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a5269..8169719343e 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -623,6 +623,115 @@ select jsonb_path_query('"2023-08-15 12:34:56 +5:30"', '$.timestamp_tz().string(
 select jsonb_path_query('"2023-08-15 12:34:56"', '$.timestamp().string()');
 rollback;
 
+-- test .ltrim()
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+select jsonb_path_query('"   hello   "', '$.ltrim(" ")');
+select jsonb_path_query('"   hello   "', '$.ltrim()');
+select jsonb_path_query('"zzzytest"', '$.ltrim("xyz")');
+select jsonb_path_query('null', '$.ltrim()');
+select jsonb_path_query('null', '$.ltrim()', silent => true);
+select jsonb_path_query('[]', '$.ltrim()');
+select jsonb_path_query('[]', 'strict $.ltrim()');
+select jsonb_path_query('{}', '$.ltrim()');
+select jsonb_path_query('[]', 'strict $.ltrim()', silent => true);
+select jsonb_path_query('{}', '$.ltrim()', silent => true);
+select jsonb_path_query('1.23', '$.ltrim()');
+select jsonb_path_query('"1.23"', '$.ltrim()');
+select jsonb_path_query('"1.23aaa"', '$.ltrim()');
+select jsonb_path_query('1234', '$.ltrim()');
+select jsonb_path_query('true', '$.ltrim()');
+select jsonb_path_query('1234', '$.ltrim().type()');
+select jsonb_path_query('[2, true]', '$.ltrim()');
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim()');
+select jsonb_path_query_array('["  maybe  ", "  yes", "  no"]', '$[*].ltrim().type()');
+
+-- test .rtrim()
+select jsonb_path_query('"   hello   "', '$.rtrim(" ")');
+select jsonb_path_query('"testxxzx"', '$.rtrim("xyz")');
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+select jsonb_path_query('"   hello   "', '$.rtrim()');
+
+-- test .btrim()
+select jsonb_path_query('"   hello   "', '$.btrim(" ")');
+select jsonb_path_query('"xyxtrimyyx"', '$.btrim("xyz")');
+select jsonb_path_query('"   hello   "', '$.btrim()');
+select jsonb_path_query('"   hello   "', '$.btrim()');
+
+-- test .lower()
+select jsonb_path_query('null', '$.lower()');
+select jsonb_path_query('null', '$.lower()', silent => true);
+select jsonb_path_query('[]', '$.lower()');
+select jsonb_path_query('[]', 'strict $.lower()');
+select jsonb_path_query('{}', '$.lower()');
+select jsonb_path_query('[]', 'strict $.lower()', silent => true);
+select jsonb_path_query('{}', '$.lower()', silent => true);
+select jsonb_path_query('1.23', '$.lower()');
+select jsonb_path_query('"1.23"', '$.lower()');
+select jsonb_path_query('"1.23aaa"', '$.lower()');
+select jsonb_path_query('1234', '$.lower()');
+select jsonb_path_query('true', '$.lower()');
+select jsonb_path_query('1234', '$.lower().type()');
+select jsonb_path_query('[2, true]', '$.lower()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].lower().type()');
+
+-- test .upper()
+select jsonb_path_query('null', '$.upper()');
+select jsonb_path_query('null', '$.upper()', silent => true);
+select jsonb_path_query('[]', '$.upper()');
+select jsonb_path_query('[]', 'strict $.upper()');
+select jsonb_path_query('{}', '$.upper()');
+select jsonb_path_query('[]', 'strict $.upper()', silent => true);
+select jsonb_path_query('{}', '$.upper()', silent => true);
+select jsonb_path_query('1.23', '$.upper()');
+select jsonb_path_query('"1.23"', '$.upper()');
+select jsonb_path_query('"1.23aaa"', '$.upper()');
+select jsonb_path_query('1234', '$.upper()');
+select jsonb_path_query('true', '$.upper()');
+select jsonb_path_query('1234', '$.upper().type()');
+select jsonb_path_query('[2, true]', '$.upper()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper()');
+select jsonb_path_query_array('["maybe", "yes", "no"]', '$[*].upper().type()');
+
+-- test .initcap()
+select jsonb_path_query('null', '$.initcap()');
+select jsonb_path_query('null', '$.initcap()', silent => true);
+select jsonb_path_query('[]', '$.initcap()');
+select jsonb_path_query('[]', 'strict $.initcap()');
+select jsonb_path_query('{}', '$.initcap()');
+select jsonb_path_query('[]', 'strict $.initcap()', silent => true);
+select jsonb_path_query('{}', '$.initcap()', silent => true);
+select jsonb_path_query('1.23', '$.initcap()');
+select jsonb_path_query('"1.23"', '$.initcap()');
+select jsonb_path_query('"1.23aaa"', '$.initcap()');
+select jsonb_path_query('1234', '$.initcap()');
+select jsonb_path_query('true', '$.initcap()');
+select jsonb_path_query('1234', '$.initcap().type()');
+select jsonb_path_query('[2, true]', '$.initcap()');
+select jsonb_path_query('["maybe yes", "probably no"]', '$.initcap()');
+
+-- Test .replace()
+select jsonb_path_query('null', '$.replace("x", "bye")');
+select jsonb_path_query('null', '$.replace("x", "bye")', silent => true);
+select jsonb_path_query('["x", "y", "z"]', '$.replace("x", "bye")');
+select jsonb_path_query('{}', '$.replace("x", "bye")');
+select jsonb_path_query('[]', 'strict $.replace("x", "bye")', silent => true);
+select jsonb_path_query('{}', '$.replace("x", "bye")', silent => true);
+select jsonb_path_query('1.23', '$.replace("x", "bye")');
+select jsonb_path_query('"hello world"', '$.replace("hello","bye")');
+select jsonb_path_query('"hello world"', '$.replace("hello","bye") starts with "bye"');
+
+-- Test .split_part()
+select jsonb_path_query('"abc~@~def~@~ghi"', '$.split_part("~@~", 2)');
+select jsonb_path_query('"abc,def,ghi,jkl"', '$.split_part(",", -2)');
+
+-- Test string methods play nicely together
+select jsonb_path_query('"hello world"', '$.replace("hello","bye").upper()');
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye")');
+select jsonb_path_query('"hElLo WorlD"', '$.upper().lower().upper().replace("HELLO", "BYE")');
+select jsonb_path_query('"hElLo WorlD"', '$.lower().upper().lower().replace("hello","bye") starts with "bye"');
+select jsonb_path_query('"   hElLo WorlD "', '$.btrim().lower().upper().lower().replace("hello","bye") starts with "bye"');
+
 -- Test .time()
 select jsonb_path_query('null', '$.time()');
 select jsonb_path_query('true', '$.time()');
diff --git a/src/test/regress/sql/jsonpath.sql b/src/test/regress/sql/jsonpath.sql
index 61a5270d4e8..7dd2e57e7a6 100644
--- a/src/test/regress/sql/jsonpath.sql
+++ b/src/test/regress/sql/jsonpath.sql
@@ -78,6 +78,37 @@ select '$.boolean()'::jsonpath;
 select '$.date()'::jsonpath;
 select '$.decimal(4,2)'::jsonpath;
 select '$.string()'::jsonpath;
+select '$.replace("hello","bye")'::jsonpath;
+select '$.lower()'::jsonpath;
+select '$.upper()'::jsonpath;
+select '$.lower().upper().lower().replace("hello","bye")'::jsonpath;
+select '$.ltrim()'::jsonpath;
+select '$.ltrim("xyz")'::jsonpath;
+select '$.rtrim()'::jsonpath;
+select '$.rtrim("xyz")'::jsonpath;
+select '$.btrim()'::jsonpath;
+select '$.btrim("xyz")'::jsonpath;
+select '$.initcap()'::jsonpath;
+select '$.split_part("~@~", 2)'::jsonpath;
+
+-- Parse errors
+select '$.replace("hello")'::jsonpath;
+select '$.replace()'::jsonpath;
+select '$.replace("hello","bye","extra")'::jsonpath;
+select '$.split_part("~@~")'::jsonpath;
+select '$.split_part()'::jsonpath;
+select '$.split_part("~@~", "hi")'::jsonpath;
+select '$.split_part("~@~", 2, "extra")'::jsonpath;
+select '$.lower("hi")'::jsonpath;
+select '$.upper("hi")'::jsonpath;
+select '$.initcap("hi")'::jsonpath;
+select '$.ltrim(42)'::jsonpath;
+select '$.ltrim("x", "y")'::jsonpath;
+select '$.rtrim(42)'::jsonpath;
+select '$.rtrim("x", "y")'::jsonpath;
+select '$.trim(42)'::jsonpath;
+select '$.trim("x", "y")'::jsonpath;
+
 select '$.time()'::jsonpath;
 select '$.time(6)'::jsonpath;
 select '$.time_tz()'::jsonpath;
diff --git a/src/test/regress/sql/sqljson_queryfuncs.sql b/src/test/regress/sql/sqljson_queryfuncs.sql
index a5d5e256d7f..d218b44ea47 100644
--- a/src/test/regress/sql/sqljson_queryfuncs.sql
+++ b/src/test/regress/sql/sqljson_queryfuncs.sql
@@ -357,7 +357,7 @@ INSERT INTO test_jsonb_constraints VALUES ('{"a": 10}', 1);
 
 DROP TABLE test_jsonb_constraints;
 
--- Test mutabilily of query functions
+-- Test mutability of query functions
 CREATE TABLE test_jsonb_mutability(js jsonb, b int);
 CREATE INDEX ON test_jsonb_mutability (JSON_QUERY(js, '$'));
 CREATE INDEX ON test_jsonb_mutability (JSON_QUERY(js, '$.a[0]'));
@@ -402,6 +402,15 @@ CREATE INDEX ON test_jsonb_mutability (JSON_QUERY(js, '$[1, 0 to $.a ? (@.dateti
 CREATE INDEX ON test_jsonb_mutability (JSON_QUERY(js, '$[1, $.a ? (@.datetime("HH:MI") == $x)]' PASSING '12:34'::time AS x));
 CREATE INDEX ON test_jsonb_mutability (JSON_VALUE(js, '$' DEFAULT random()::int ON ERROR));
 
+CREATE INDEX ON test_jsonb_mutability (JSON_QUERY(js, '$.rtrim()'));
+CREATE INDEX ON test_jsonb_mutability (JSON_QUERY(js, '$.ltrim()'));
+CREATE INDEX ON test_jsonb_mutability (JSON_QUERY(js, '$.btrim()'));
+CREATE INDEX ON test_jsonb_mutability (JSON_QUERY(js, '$.lower()'));
+CREATE INDEX ON test_jsonb_mutability (JSON_QUERY(js, '$.upper()'));
+CREATE INDEX ON test_jsonb_mutability (JSON_QUERY(js, '$.initcap()'));
+CREATE INDEX ON test_jsonb_mutability (JSON_QUERY(js, '$.replace("hello", "bye")'));
+CREATE INDEX ON test_jsonb_mutability (JSON_QUERY(js, '$.split_part(",", 2)'));
+
 -- DEFAULT expression
 CREATE OR REPLACE FUNCTION ret_setint() RETURNS SETOF integer AS
 $$
-- 
2.51.0