Tarlika Elisabeth Schmitz wrote: > On Fri, 20 Feb 2009 19:06:48 +0000 > Richard Huxton <d...@archonet.com> wrote: >> try something like: >> >> SELECT t1.d, t1.s, t1.c, count(*) >> FROM t1 >> LEFT JOIN ( >> SELECT d,s,c FROM t2 WHERE x >> ) AS t2_true USING (d,s,c) >> GROUP BY t1.d, t1.s, t1.c; >> >> Warning - not tested > > Many thanks for the quick reply. > > > This suggestion does not work as it returns a count of 1 even when > there are no rows in t2 that match (d,s,c) in T1.
Ah, then rather than count(*) you'll want count(t2_true.d) so when you get a null because of no match it's not counted. You can use any column from t2_true. -- Richard Huxton Archonet Ltd -- Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-sql
