On Mon, 2009-05-18 at 20:24 +0200, hubert depesz lubaczewski wrote: > I was under impression that select distinct on (xx) ... > will fail if xx doesn't match the left most part of order by. i.e. it > requires order by xx, while allowing order by xx, something, else. > > But it seems you can run the query with no order by clause at all. > > is it intentional?
This is documented behavior: "Note that the 'first row' of each set is unpredictable unless ORDER BY is used to ensure that the desired row appears first." http://www.postgresql.org/docs/8.4/static/sql-select.html#SQL-DISTINCT Regards, Jeff Davis -- Sent via pgsql-bugs mailing list (pgsql-bugs@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-bugs
