On Wed, Dec 8, 2010 at 7:15 AM, Andre Lopes <lopes80andre@xxxxxxxxx> wrote: > Hi, > > I need to obtain the maximum value of a date, but that comparison will be > made between 3 tables... I will explain better with a query... > > [code] > select > a.last_refresh_date as d1, ae.last_refresh_date as d2, ha.last_refresh_date > as d3 > from tbl1 a > join tbl2 ae on a.id_anuncio_externo = ae.id_anuncio_externo > join tbl3 ha on a.id_anuncio_externo = ha.id_anuncio_externo > [/code] > > My question is how is the best way to obtain with date is the greatest, d1, > d2 or d3 If you don't need to know which table it came from I would probably try select a.last_refresh_date as d1, NULL as d2, NULL as d3 FROM tbl1 as a UNION ALL ... -- Jon -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
