From ad885e2677754c8adbfa847d20812ce6b7594eb6 Mon Sep 17 00:00:00 2001 From: Heikki Linnakangas Date: Sat, 8 Oct 2011 11:17:40 +0300 Subject: [PATCH] Don't let transform_null_equals=on affect CASE foo WHEN NULL ... constructs. transform_null_equals is only supposed to affect "foo = NULL" expressions given directly by the user, not the internal "foo = NULL" expression generated from CASE-WHEN. This fixes bug #6242, reported by Sergey. Backpatch to all supported branches. --- src/backend/parser/parse_expr.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/src/backend/parser/parse_expr.c b/src/backend/parser/parse_expr.c index 65d03adc49..79328c9979 100644 --- a/src/backend/parser/parse_expr.c +++ b/src/backend/parser/parse_expr.c @@ -836,12 +836,15 @@ transformAExprOp(ParseState *pstate, A_Expr *a) /* * Special-case "foo = NULL" and "NULL = foo" for compatibility with * standards-broken products (like Microsoft's). Turn these into IS NULL - * exprs. + * exprs. (If either side is a CaseTestExpr, then the expression was + * generated internally from a CASE-WHEN expression, and + * transform_null_equals does not apply.) */ if (Transform_null_equals && list_length(a->name) == 1 && strcmp(strVal(linitial(a->name)), "=") == 0 && - (exprIsNullConstant(lexpr) || exprIsNullConstant(rexpr))) + (exprIsNullConstant(lexpr) || exprIsNullConstant(rexpr)) && + (!IsA(lexpr, CaseTestExpr) && !IsA(rexpr, CaseTestExpr))) { NullTest *n = makeNode(NullTest); -- 2.40.0