Hi, I tried and this does does not work either. Thank you, Ioana --- "Jim C. Nasby" <jim@xxxxxxxxx> wrote: > On Wed, Oct 18, 2006 at 03:32:15PM -0700, Jeff Davis > wrote: > > On Wed, 2006-10-18 at 17:10 -0500, Jim C. Nasby > wrote: > > > Sorry, don't have the earlier part of this > thread, but what about... > > > > > > SELECT greatest(max(a), max(b)) ... > > > > > > ? > > > > To fill you in, we're trying to get the max of a > union (a view across > > two physical tables). > > UNION or UNION ALL? You definitely don't want to do > a plain UNION if you > can possibly avoid it. > > > It can be done if you're creative with the query; > I suggested a query > > that selected the max of the max()es of the > individual tables. Your > > query could work too. However, the trick would be > getting postgresql to > > recognize that it can transform "SELECT max(x) > FROM foo" into that, > > where foo is a view of a union. > > > > If PostgreSQL could sort the result of a union by > merging the results of > > two index scans, I think the problem would be > solved. Is there something > > preventing this, or is it just something that > needs to be added to the > > planner? > > Hrm... it'd be worth trying the old ORDER BY ... > LIMIT 1 trick just to > see if that worked in this case, but I don't have > much hope for that. > -- > Jim Nasby > jim@xxxxxxxxx > EnterpriseDB http://enterprisedb.com > 512.569.9461 (cell) > __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com
