In response to Vratislav Benes : > but when I try make a condition by join table, the query plan is not optimal: > > > select period_id from periods where y=2009 and w=14; > period_id > ----------- > 704 > (1 row) > > > explain select sum(s_pcs),sum(s_val) > from data d inner join periods p on d.period_id=p.period_id > where p.y=2009 and p.w=14; How about select sum(s_pcs),sum(s_val) from data d inner join periods p on d.period_id=p.period_id where p.y=2009 and p.w=14 and p.period_id in (select period_id from periods where y=2009 and w=14); Untested. Andreas -- Andreas Kretschmer Kontakt: Heynitz: 035242/47150, D1: 0160/7141639 (mehr: -> Header) -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
