diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 5094226..aae35d8 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -288,6 +288,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 %type <list>	TriggerEvents TriggerOneEvent
 %type <value>	TriggerFuncArg
 %type <node>	TriggerWhen
+%type <ival>	opt_ignore_nulls
 
 %type <list>	event_trigger_when_list event_trigger_value_list
 %type <defelt>	event_trigger_when_item
@@ -401,7 +402,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 %type <node>	columnDef columnOptions
 %type <defelt>	def_elem reloption_elem old_aggr_elem
 %type <node>	def_arg columnElem where_clause where_or_current_clause
-				a_expr b_expr c_expr func_expr AexprConst indirection_el
+				a_expr b_expr c_expr AexprConst indirection_el
 				columnref in_expr having_clause func_table array_expr
 				ExclusionWhereClause
 %type <list>	ExclusionConstraintList ExclusionConstraintElem
@@ -481,6 +482,8 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 %type <ival>	document_or_content
 %type <boolean> xml_whitespace_option
 
+%type <node>	func_application func_expr_common_subexpr
+%type <node>	func_expr func_expr_windowless
 %type <node>	common_table_expr
 %type <with>	with_clause opt_with_clause
 %type <list>	cte_list
@@ -543,7 +546,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 
 	HANDLER HAVING HEADER_P HOLD HOUR_P
 
-	IDENTITY_P IF_P ILIKE IMMEDIATE IMMUTABLE IMPLICIT_P IN_P
+	IDENTITY_P IF_P IGNORE ILIKE IMMEDIATE IMMUTABLE IMPLICIT_P IN_P
 	INCLUDING INCREMENT INDEX INDEXES INHERIT INHERITS INITIALLY INLINE_P
 	INNER_P INOUT INPUT_P INSENSITIVE INSERT INSTEAD INT_P INTEGER
 	INTERSECT INTERVAL INTO INVOKER IS ISNULL ISOLATION
@@ -573,7 +576,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 
 	RANGE READ REAL REASSIGN RECHECK RECURSIVE REF REFERENCES REFRESH REINDEX
 	RELATIVE_P RELEASE RENAME REPEATABLE REPLACE REPLICA
-	RESET RESTART RESTRICT RETURNING RETURNS REVOKE RIGHT ROLE ROLLBACK
+	RESET RESPECT RESTART RESTRICT RETURNING RETURNS REVOKE RIGHT ROLE ROLLBACK
 	ROW ROWS RULE
 
 	SAVEPOINT SCHEMA SCROLL SEARCH SECOND_P SECURITY SELECT SEQUENCE SEQUENCES
@@ -6132,7 +6135,7 @@ index_elem:	ColId opt_collate opt_class opt_asc_desc opt_nulls_order
 					$$->ordering = $4;
 					$$->nulls_ordering = $5;
 				}
-			| func_expr opt_collate opt_class opt_asc_desc opt_nulls_order
+			| func_expr_windowless opt_collate opt_class opt_asc_desc opt_nulls_order
 				{
 					$$ = makeNode(IndexElem);
 					$$->name = NULL;
@@ -9894,11 +9897,9 @@ relation_expr_opt_alias: relation_expr					%prec UMINUS
 				}
 		;
 
-
-func_table: func_expr								{ $$ = $1; }
+func_table: func_expr_windowless					{ $$ = $1; }
 		;
 
-
 where_clause:
 			WHERE a_expr							{ $$ = $2; }
 			| /*EMPTY*/								{ $$ = NULL; }
@@ -11079,15 +11080,7 @@ c_expr:		columnref								{ $$ = $1; }
 				}
 		;
 
-/*
- * func_expr is split out from c_expr just so that we have a classification
- * for "everything that is a function call or looks like one".  This isn't
- * very important, but it saves us having to document which variants are
- * legal in the backwards-compatible functional-index syntax for CREATE INDEX.
- * (Note that many of the special SQL functions wouldn't actually make any
- * sense as functional index entries, but we ignore that consideration here.)
- */
-func_expr:	func_name '(' ')' over_clause
+func_application: func_name '(' ')'
 				{
 					FuncCall *n = makeNode(FuncCall);
 					n->funcname = $1;
@@ -11096,11 +11089,11 @@ func_expr:	func_name '(' ')' over_clause
 					n->agg_star = FALSE;
 					n->agg_distinct = FALSE;
 					n->func_variadic = FALSE;
-					n->over = $4;
+					n->over = NULL;
 					n->location = @1;
 					$$ = (Node *)n;
 				}
-			| func_name '(' func_arg_list ')' over_clause
+			| func_name '(' func_arg_list ')'
 				{
 					FuncCall *n = makeNode(FuncCall);
 					n->funcname = $1;
@@ -11109,11 +11102,11 @@ func_expr:	func_name '(' ')' over_clause
 					n->agg_star = FALSE;
 					n->agg_distinct = FALSE;
 					n->func_variadic = FALSE;
-					n->over = $5;
+					n->over = NULL;
 					n->location = @1;
 					$$ = (Node *)n;
 				}
-			| func_name '(' VARIADIC func_arg_expr ')' over_clause
+			| func_name '(' VARIADIC func_arg_expr ')'
 				{
 					FuncCall *n = makeNode(FuncCall);
 					n->funcname = $1;
@@ -11122,11 +11115,11 @@ func_expr:	func_name '(' ')' over_clause
 					n->agg_star = FALSE;
 					n->agg_distinct = FALSE;
 					n->func_variadic = TRUE;
-					n->over = $6;
+					n->over = NULL;
 					n->location = @1;
 					$$ = (Node *)n;
 				}
-			| func_name '(' func_arg_list ',' VARIADIC func_arg_expr ')' over_clause
+			| func_name '(' func_arg_list ',' VARIADIC func_arg_expr ')'
 				{
 					FuncCall *n = makeNode(FuncCall);
 					n->funcname = $1;
@@ -11135,11 +11128,11 @@ func_expr:	func_name '(' ')' over_clause
 					n->agg_star = FALSE;
 					n->agg_distinct = FALSE;
 					n->func_variadic = TRUE;
-					n->over = $8;
+					n->over = NULL;
 					n->location = @1;
 					$$ = (Node *)n;
 				}
-			| func_name '(' func_arg_list sort_clause ')' over_clause
+			| func_name '(' func_arg_list sort_clause ')'
 				{
 					FuncCall *n = makeNode(FuncCall);
 					n->funcname = $1;
@@ -11148,11 +11141,11 @@ func_expr:	func_name '(' ')' over_clause
 					n->agg_star = FALSE;
 					n->agg_distinct = FALSE;
 					n->func_variadic = FALSE;
-					n->over = $6;
+					n->over = NULL;
 					n->location = @1;
 					$$ = (Node *)n;
 				}
-			| func_name '(' ALL func_arg_list opt_sort_clause ')' over_clause
+			| func_name '(' ALL func_arg_list opt_sort_clause ')'
 				{
 					FuncCall *n = makeNode(FuncCall);
 					n->funcname = $1;
@@ -11165,11 +11158,11 @@ func_expr:	func_name '(' ')' over_clause
 					 * for that in FuncCall at the moment.
 					 */
 					n->func_variadic = FALSE;
-					n->over = $7;
+					n->over = NULL;
 					n->location = @1;
 					$$ = (Node *)n;
 				}
-			| func_name '(' DISTINCT func_arg_list opt_sort_clause ')' over_clause
+			| func_name '(' DISTINCT func_arg_list opt_sort_clause ')'
 				{
 					FuncCall *n = makeNode(FuncCall);
 					n->funcname = $1;
@@ -11178,11 +11171,11 @@ func_expr:	func_name '(' ')' over_clause
 					n->agg_star = FALSE;
 					n->agg_distinct = TRUE;
 					n->func_variadic = FALSE;
-					n->over = $7;
+					n->over = NULL;
 					n->location = @1;
 					$$ = (Node *)n;
 				}
-			| func_name '(' '*' ')' over_clause
+			| func_name '(' '*' ')'
 				{
 					/*
 					 * We consider AGGREGATE(*) to invoke a parameterless
@@ -11201,11 +11194,48 @@ func_expr:	func_name '(' ')' over_clause
 					n->agg_star = TRUE;
 					n->agg_distinct = FALSE;
 					n->func_variadic = FALSE;
-					n->over = $5;
+					n->over = NULL;
 					n->location = @1;
 					$$ = (Node *)n;
 				}
-			| COLLATION FOR '(' a_expr ')'
+        ;
+
+
+/*
+ * func_expr and its cousin func_expr_windowless is split out from c_expr just 
+ * so that we have classifications for "everything that is a function call or 
+ * looks like one".  This isn't very important, but it saves us having to document 
+ * which variants are legal in the backwards-compatible functional-index syntax 
+ * for CREATE INDEX.
+ * (Note that many of the special SQL functions wouldn't actually make any
+ * sense as functional index entries, but we ignore that consideration here.)
+ */
+func_expr: func_application over_clause 
+				{
+              		FuncCall *n = (FuncCall*)$1;
+					n->over = $2;
+					$$ = (Node*)n;
+				} 
+			| func_expr_common_subexpr
+				{ $$ = $1; }
+		;
+
+/* 
+ * As func_expr but does not accept WINDOW functions directly (they
+ * can still be contained in arguments for functions etc.)
+ * Use this when window expressions are not allowed, so to decomplicate
+ * the grammar. (e.g. in CREATE INDEX)
+ */
+func_expr_windowless: 
+			func_application						{ $$ = $1; }
+			| func_expr_common_subexpr 				{ $$ = $1; }
+		;
+
+/*
+ * Special expression 
+ */
+func_expr_common_subexpr:	
+			COLLATION FOR '(' a_expr ')'
 				{
 					FuncCall *n = makeNode(FuncCall);
 					n->funcname = SystemFuncName("pg_collation_for");
@@ -11752,16 +11782,25 @@ window_definition:
 				}
 		;
 
-over_clause: OVER window_specification
-				{ $$ = $2; }
-			| OVER ColId
+opt_ignore_nulls: 
+			IGNORE NULLS_P						{ $$ = FRAMEOPTION_IGNORE_NULLS; }
+			| RESPECT NULLS_P					{ $$ = 0; }
+			| /* EMPTY */						{ $$ = 0; } 
+		;
+
+over_clause: opt_ignore_nulls OVER window_specification
+				{ 
+					$3->frameOptions |= $1;
+					$$ = $3;
+				}
+			| opt_ignore_nulls OVER ColId
 				{
 					WindowDef *n = makeNode(WindowDef);
-					n->name = $2;
+					n->name = $3;
 					n->refname = NULL;
 					n->partitionClause = NIL;
 					n->orderClause = NIL;
-					n->frameOptions = FRAMEOPTION_DEFAULTS;
+					n->frameOptions = FRAMEOPTION_DEFAULTS | $1;
 					n->startOffset = NULL;
 					n->endOffset = NULL;
 					n->location = @2;
@@ -12740,6 +12779,7 @@ unreserved_keyword:
 			| HOUR_P
 			| IDENTITY_P
 			| IF_P
+			| IGNORE
 			| IMMEDIATE
 			| IMMUTABLE
 			| IMPLICIT_P
@@ -12827,6 +12867,7 @@ unreserved_keyword:
 			| REPLACE
 			| REPLICA
 			| RESET
+			| RESPECT
 			| RESTART
 			| RESTRICT
 			| RETURNS
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 6723647..71b44d5 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -435,6 +435,7 @@ typedef struct WindowDef
 #define FRAMEOPTION_END_VALUE_PRECEDING			0x00800 /* end is V. P. */
 #define FRAMEOPTION_START_VALUE_FOLLOWING		0x01000 /* start is V. F. */
 #define FRAMEOPTION_END_VALUE_FOLLOWING			0x02000 /* end is V. F. */
+#define FRAMEOPTION_IGNORE_NULLS                0x04000 
 
 #define FRAMEOPTION_START_VALUE \
 	(FRAMEOPTION_START_VALUE_PRECEDING | FRAMEOPTION_START_VALUE_FOLLOWING)
diff --git a/src/include/parser/kwlist.h b/src/include/parser/kwlist.h
index 68a13b7..2acf073 100644
--- a/src/include/parser/kwlist.h
+++ b/src/include/parser/kwlist.h
@@ -179,6 +179,7 @@ PG_KEYWORD("hold", HOLD, UNRESERVED_KEYWORD)
 PG_KEYWORD("hour", HOUR_P, UNRESERVED_KEYWORD)
 PG_KEYWORD("identity", IDENTITY_P, UNRESERVED_KEYWORD)
 PG_KEYWORD("if", IF_P, UNRESERVED_KEYWORD)
+PG_KEYWORD("ignore", IGNORE, UNRESERVED_KEYWORD)
 PG_KEYWORD("ilike", ILIKE, TYPE_FUNC_NAME_KEYWORD)
 PG_KEYWORD("immediate", IMMEDIATE, UNRESERVED_KEYWORD)
 PG_KEYWORD("immutable", IMMUTABLE, UNRESERVED_KEYWORD)
@@ -312,6 +313,7 @@ PG_KEYWORD("repeatable", REPEATABLE, UNRESERVED_KEYWORD)
 PG_KEYWORD("replace", REPLACE, UNRESERVED_KEYWORD)
 PG_KEYWORD("replica", REPLICA, UNRESERVED_KEYWORD)
 PG_KEYWORD("reset", RESET, UNRESERVED_KEYWORD)
+PG_KEYWORD("respect", RESPECT, UNRESERVED_KEYWORD)
 PG_KEYWORD("restart", RESTART, UNRESERVED_KEYWORD)
 PG_KEYWORD("restrict", RESTRICT, UNRESERVED_KEYWORD)
 PG_KEYWORD("returning", RETURNING, RESERVED_KEYWORD)
diff --git a/src/test/regress/expected/window.out b/src/test/regress/expected/window.out
index 752c7b4..cb34a7c 100644
--- a/src/test/regress/expected/window.out
+++ b/src/test/regress/expected/window.out
@@ -989,9 +989,9 @@ ERROR:  window functions are not allowed in GROUP BY
 LINE 1: SELECT rank() OVER (ORDER BY 1), count(*) FROM empsalary GRO...
                ^
 SELECT * FROM rank() OVER (ORDER BY random());
-ERROR:  window functions are not allowed in functions in FROM
+ERROR:  syntax error at or near "OVER"
 LINE 1: SELECT * FROM rank() OVER (ORDER BY random());
-                      ^
+                             ^
 DELETE FROM empsalary WHERE (rank() OVER (ORDER BY random())) > 10;
 ERROR:  window functions are not allowed in WHERE
 LINE 1: DELETE FROM empsalary WHERE (rank() OVER (ORDER BY random())...