On Fri, 26 Dec 2008 12:04:48 -0800 David Fetter <david@xxxxxxxxxx> wrote: > On Fri, Dec 26, 2008 at 08:03:30PM +0100, Ivan Sergio Borgonovo > wrote: > > > > aggregate_name (DISTINCT expression [, expression] ) > > > In 8.4, you'll be able to do: > > > WITH d AS ( > > > SELECT DISTINCT c1, c2 FROM table1 > > > ) > > > SELECT count(*) FROM d; > > Nice, but what will be the difference from > > select count(*) from (select distinct c1, c2 from t); > > ? > > Optimisation? > None especially. So what would be the advantage compared to subselect? > > Furthermore... I was actually looking at docs because I needed to > > find a way supported by both postgresql and mysql > > Generally, it's *not* a good idea to try to support more than one > back-end. You wind up maintaining several disparate code bases, Not really my main target... I was just investigating if it could come for free ;) -- Ivan Sergio Borgonovo http://www.webthatworks.it -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
