On Tue, Feb 04, 2003 at 09:08:56 -0500, Wei Weng <[EMAIL PROTECTED]> wrote: > It is a query that looks like > > SELECT target1, target2... targetn, SUN(t.qty) > FROM Table t > GROUP BY target1 > HAVING SUM(t.qty)>=10 > > You can replace SUM(t.qty)>=10 with other aggregate constraints.
There were some recent changes to allow groups to use hashes that may help for queries like this. This can save a sort step or using an index scan. In theory you might be able to make some other speed ups by taking advantage of properties of specific aggregate functions (in particular that several common ones monotonicly increase or decrease as they are being calculated) and if doing an index scan on the fields used for group you might be able to skip a lot of rows. I expect that this situation would come up pretty rarely though. ---------------------------(end of broadcast)--------------------------- TIP 6: Have you searched our list archives? http://archives.postgresql.org
