From 1f5ca045a435bc6aa9c98d7296973925c5208add Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Wed, 21 Jun 2006 18:30:11 +0000 Subject: [PATCH] Disallow aggregate functions in UPDATE commands (unless within a sub-SELECT). This is disallowed by the SQL spec because it doesn't have any very sensible interpretation. Historically Postgres has allowed it but behaved strangely. As of PG 8.1 a server crash is possible if the MIN/MAX index optimization gets applied; rather than try to "fix" that, it seems best to just enforce the spec restriction. Per report from Josh Drake and Alvaro Herrera. --- src/backend/parser/analyze.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c index 566c9a0488..4e30d2b96f 100644 --- a/src/backend/parser/analyze.c +++ b/src/backend/parser/analyze.c @@ -6,7 +6,7 @@ * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $PostgreSQL: pgsql/src/backend/parser/analyze.c,v 1.334 2006/04/30 18:30:39 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/parser/analyze.c,v 1.335 2006/06/21 18:30:11 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -1613,7 +1613,7 @@ transformRuleStmt(ParseState *pstate, RuleStmt *stmt, if (pstate->p_hasAggs) ereport(ERROR, (errcode(ERRCODE_GROUPING_ERROR), - errmsg("rule WHERE condition may not contain aggregate functions"))); + errmsg("cannot use aggregate function in rule WHERE condition"))); /* save info about sublinks in where clause */ qry->hasSubLinks = pstate->p_hasSubLinks; @@ -2346,9 +2346,16 @@ transformUpdateStmt(ParseState *pstate, UpdateStmt *stmt) qry->jointree = makeFromExpr(pstate->p_joinlist, qual); qry->hasSubLinks = pstate->p_hasSubLinks; - qry->hasAggs = pstate->p_hasAggs; + + /* + * Top-level aggregates are simply disallowed in UPDATE, per spec. + * (From an implementation point of view, this is forced because the + * implicit ctid reference would otherwise be an ungrouped variable.) + */ if (pstate->p_hasAggs) - parseCheckAggregates(pstate, qry); + ereport(ERROR, + (errcode(ERRCODE_GROUPING_ERROR), + errmsg("cannot use aggregate function in UPDATE"))); /* * Now we are done with SELECT-like processing, and can get on with -- 2.40.0