On Mon, Jul 20, 2009 at 2:37 PM, Robert James<[email protected]> wrote: > I have two queries which should be equivalent. The Planner plans them > differently, although they are both about the same time. Can someone > explain why? > select word from dict > where > word in > (select substr('moon', 0, generate_series(3,length('moon')))) > > select * from dict > inner join (select substr('moon', 0, generate_series(3,length('moon')))) as > m > on dict.word = m.substr > > Is one preferred?
it is hard to say from your example. But in my general expierence, I noticed similar thing many times. Needless to say, I prefer personally to choose JOINs instead of IN(), because those tend to be faster on postgresql. -- Sent via pgsql-general mailing list ([email protected]) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
