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Make the behavior of HAVING without GROUP BY conform to the SQL spec.

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Formerly, if such a clause contained no aggregate functions we mistakenly
treated it as equivalent to WHERE.  Per spec it must cause the query to
be treated as a grouped query of a single group, the same as appearance
of aggregate functions would do.  Also, the HAVING filter must execute
after aggregate function computation even if it itself contains no
aggregate functions.
This commit is contained in:
Tom Lane
2005-03-10 23:21:26 +00:00
parent 609e32b929
commit 595ed2a855
20 changed files with 385 additions and 238 deletions
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11
src/backend/optimizer/util/pathnode.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/util/pathnode.c,v 1.111 2004/12/31 22:00:23 pgsql Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/util/pathnode.c,v 1.112 2005/03/10 23:21:22 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -797,6 +797,15 @@ is_distinct_query(Query *query)
if (!gl) /* got to the end? */
return true;
}
else
{
/*
* If we have no GROUP BY, but do have aggregates or HAVING, then
* the result is at most one row so it's surely unique.
*/
if (query->hasAggs || query->havingQual)
return true;
}
/*
* XXX Are there any other cases in which we can easily see the result