On Tue, Jan 09, 2007 at 05:07:03PM -0800, Brian Herlihy wrote: > Actually, as I recently discovered, GROUP BY is faster than DISTINCT. It's > just due to how they are implemented, so don't go looking for any deep > reason :) The thread "GROUP BY vs DISTINCT" from 2006-12-20 discusses it. > DISTINCT sorts the results to find the unique rows, but GROUP BY uses a > hash.
Actually, GROUP BY _can_ use a sort too, it's just that a hash is usually faster. /* Steinar */ -- Homepage: http://www.sesse.net/ ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings
