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Date: Thu, 6 Mar 2003 22:11:03 -0800 (PST)
From: Stephan Szabo <sszabo@megazone23.bigpanda.com>
To: Rajesh Kumar Mallah <mallah@trade-india.com>
Cc: Tomasz Myrta <jasiek@klaster.net>, <pgsql-sql@postgresql.org>
Subject: Re: sql question regarding count(*)
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On Fri, 7 Mar 2003, Rajesh Kumar Mallah wrote:

> Tomasz did you notice the two queries are totally differet on different
> tables?

A count() on a non-grouped table returns 1 row.

A grouped table returns 1 row per group.  If there are no groups, no rows
are returned.  If the groups are filtered by a having clause, it might
also return no rows.