On Fri, Jul 10, 2009 at 6:37 PM, Jeff Davis<pgsql@xxxxxxxxxxx> wrote: > > -- foo has a primary key > SELECT * FROM foo UNION SELECT * FROM foo; > > That's logically equivalent to: > > SELECT * FROM foo; > > But postgresql will add a sort anyway. Well no, it's equivalent to SELECT DISTINCT * FROM foo; -- greg http://mit.edu/~gsstark/resume.pdf -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
