diff options
Diffstat (limited to 'src/backend/parser/gram.y')
| -rw-r--r-- | src/backend/parser/gram.y | 29 |
1 files changed, 8 insertions, 21 deletions
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y index 5a7dff919d..c593196dfc 100644 --- a/src/backend/parser/gram.y +++ b/src/backend/parser/gram.y @@ -11,7 +11,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.403 2003/02/13 05:25:24 momjian Exp $ + * $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.404 2003/02/16 02:30:38 tgl Exp $ * * HISTORY * AUTHOR DATE MAJOR EVENT @@ -6650,6 +6650,10 @@ in_expr: select_with_parens * COALESCE(a,b,...) * same as CASE WHEN a IS NOT NULL THEN a WHEN b IS NOT NULL THEN b ... END * - thomas 1998-11-09 + * + * NULLIF and COALESCE have become first class nodes to + * prevent double evaluation of arguments. + * - Kris Jurka 2003-02-11 */ case_expr: CASE case_arg when_clause_list case_default END_P { @@ -6661,29 +6665,12 @@ case_expr: CASE case_arg when_clause_list case_default END_P } | NULLIF '(' a_expr ',' a_expr ')' { - CaseExpr *c = makeNode(CaseExpr); - CaseWhen *w = makeNode(CaseWhen); - - w->expr = (Expr *) makeSimpleA_Expr(AEXPR_OP, "=", $3, $5); - /* w->result is left NULL */ - c->args = makeList1(w); - c->defresult = (Expr *) $3; - $$ = (Node *)c; + $$ = (Node *) makeSimpleA_Expr(AEXPR_NULLIF, "=", $3, $5); } | COALESCE '(' expr_list ')' { - CaseExpr *c = makeNode(CaseExpr); - List *l; - foreach (l,$3) - { - CaseWhen *w = makeNode(CaseWhen); - NullTest *n = makeNode(NullTest); - n->arg = lfirst(l); - n->nulltesttype = IS_NOT_NULL; - w->expr = (Expr *) n; - w->result = lfirst(l); - c->args = lappend(c->args, w); - } + CoalesceExpr *c = makeNode(CoalesceExpr); + c->args = $3; $$ = (Node *)c; } ; |