From 8ccb3f1043c6b58d48895273a558674d07f0d5c6 Mon Sep 17 00:00:00 2001 From: Amit Langote Date: Fri, 6 Nov 2026 11:29:02 +0900 Subject: [PATCH v2-REL_17-19] JSON_TABLE: fix missing collation assignments transformJsonTable() transforms the context item and the PASSING arguments into the JsonExpr stored in TableFunc.docexpr, and copies the transformed PASSING arguments into TableFunc.passingvalexprs, but never ran assign_expr_collations() over them. That is needed here because assign_query_collations() doesn't look into the range table, which is why transformRangeTableFunc() does it for XMLTABLE, as does transformJsonTableColumn() for JSON_TABLE's own column expressions. As a result, expressions in there were left without collations. A text comparison failed with "could not determine which collation to use for string comparison", even with an explicit COLLATE clause, and a row comparison was left with an empty inputcollids list, which made the executor compare zero columns and return the result for equal rows (so ROW(1, 2) < ROW(3, 4) yielded false), or trip an assertion in ExecInitExprRec() in assert-enabled builds. Fix by calling assign_expr_collations() on the transformed JsonExpr, before the PASSING arguments are copied out of it. Oversight in commit de3600452b6, so back-patch to 17. Bug: #19768 Reported-by: Venu Kummari Author: Venu Kummari Discussion: https://postgr.es/m/19768-3633daa830be95db@postgresql.org Backpatch-through: 17 --- src/backend/parser/parse_jsontable.c | 8 +++++ .../regress/expected/sqljson_jsontable.out | 30 +++++++++++++++++++ src/test/regress/sql/sqljson_jsontable.sql | 11 +++++++ 3 files changed, 49 insertions(+) diff --git a/src/backend/parser/parse_jsontable.c b/src/backend/parser/parse_jsontable.c index 7a71f6a6363..7c7399928b8 100644 --- a/src/backend/parser/parse_jsontable.c +++ b/src/backend/parser/parse_jsontable.c @@ -136,6 +136,14 @@ transformJsonTable(ParseState *pstate, JsonTable *jt) jfe->location = jt->location; tf->docexpr = transformExpr(pstate, (Node *) jfe, EXPR_KIND_FROM_FUNCTION); + /* + * Assign collations now, because assign_query_collations() doesn't look + * into the range table. This must happen before the PASSING arguments + * are copied into tf->passingvalexprs below, so that the copies carry + * the collations too. + */ + assign_expr_collations(pstate, tf->docexpr); + /* * Create a JsonTablePlan that will generate row pattern that becomes * source data for JSON path expressions in jt->columns. This also adds diff --git a/src/test/regress/expected/sqljson_jsontable.out b/src/test/regress/expected/sqljson_jsontable.out index fe4a0f54590..14c396eeed3 100644 --- a/src/test/regress/expected/sqljson_jsontable.out +++ b/src/test/regress/expected/sqljson_jsontable.out @@ -1286,3 +1286,33 @@ CREATE OR REPLACE VIEW public.json_table_view9 AS ) ) DROP VIEW json_table_view8, json_table_view9; +-- Collations must be assigned to expressions in the context item and in +-- the PASSING arguments (bug #19768) +SELECT * FROM JSON_TABLE(jsonb_build_object('k', ROW(1, 2) < ROW(3, 4)), '$' + COLUMNS (a bool PATH '$.k')); + a +--- + t +(1 row) + +SELECT * FROM JSON_TABLE(jsonb_build_object('k', 'a' < 'b' COLLATE "C"), '$' + COLUMNS (a bool PATH '$.k')); + a +--- + t +(1 row) + +SELECT * FROM JSON_TABLE(jsonb '{}', '$' PASSING 'a' < 'b' COLLATE "C" AS x + COLUMNS (a bool PATH '$x')); + a +--- + t +(1 row) + +SELECT * FROM JSON_TABLE(jsonb '{}', '$' PASSING ROW(1, 2) < ROW(3, 4) AS x + COLUMNS (a bool PATH '$x')); + a +--- + t +(1 row) + diff --git a/src/test/regress/sql/sqljson_jsontable.sql b/src/test/regress/sql/sqljson_jsontable.sql index 60ce4f0429f..ecefe9b765c 100644 --- a/src/test/regress/sql/sqljson_jsontable.sql +++ b/src/test/regress/sql/sqljson_jsontable.sql @@ -624,3 +624,14 @@ CREATE VIEW json_table_view9 AS SELECT * from JSON_TABLE('"a"', '$' COLUMNS (a t \sv json_table_view9; DROP VIEW json_table_view8, json_table_view9; + +-- Collations must be assigned to expressions in the context item and in +-- the PASSING arguments (bug #19768) +SELECT * FROM JSON_TABLE(jsonb_build_object('k', ROW(1, 2) < ROW(3, 4)), '$' + COLUMNS (a bool PATH '$.k')); +SELECT * FROM JSON_TABLE(jsonb_build_object('k', 'a' < 'b' COLLATE "C"), '$' + COLUMNS (a bool PATH '$.k')); +SELECT * FROM JSON_TABLE(jsonb '{}', '$' PASSING 'a' < 'b' COLLATE "C" AS x + COLUMNS (a bool PATH '$x')); +SELECT * FROM JSON_TABLE(jsonb '{}', '$' PASSING ROW(1, 2) < ROW(3, 4) AS x + COLUMNS (a bool PATH '$x')); -- 2.47.3