From a497d39fdd4aca2db190b21153e19093adb3dec7 Mon Sep 17 00:00:00 2001 From: jian he Date: Thu, 29 Jan 2026 09:10:02 +0800 Subject: [PATCH v1 1/1] ERROR: failed to find conversion function from unknown to text demo: create table t(a text); select cast(a as unknown) from t; discussion: https://postgr.es/m/ --- src/backend/parser/parse_coerce.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/src/backend/parser/parse_coerce.c b/src/backend/parser/parse_coerce.c index 913ca53666f..68ac99e471c 100644 --- a/src/backend/parser/parse_coerce.c +++ b/src/backend/parser/parse_coerce.c @@ -411,6 +411,16 @@ coerce_type(ParseState *pstate, Node *node, } return result; } + + if (targetTypeId == UNKNOWNOID) + { + Oid inputBaseTypeId = getBaseType(inputTypeId); + TYPCATEGORY s_typcategory = TypeCategory(inputBaseTypeId); + + if (s_typcategory == TYPCATEGORY_STRING) + return node; + } + pathtype = find_coercion_pathway(targetTypeId, inputTypeId, ccontext, &funcId); if (pathtype != COERCION_PATH_NONE) -- 2.34.1