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Disallow aggregate functions in UPDATE commands (unless within a sub-SELECT).

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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.
This commit is contained in:
Tom Lane 2006-06-21 18:30:11 +00:00
parent e256bafaa2
commit 1f5ca045a4
1 changed files with 11 additions and 4 deletions
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15
src/backend/parser/analyze.c
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@ -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