"Diehl, Jeffrey" <[EMAIL PROTECTED]> writes: > Ok, can someone explain to me why this first query might run faster than the > second? > select src,dst,count(dst) from data; > select src,dst,count(*) from data;
Hmm, I'd expect the second to be marginally faster. count(*) counts the number of rows matching the WHERE condition; count(foo) counts the number of rows matching the WHERE condition for which foo is not NULL. So count(foo) ought to involve a couple extra cycles to test for non-NULL-ness of the specified field. But it's hard to believe you could measure the difference --- what results are you getting? regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 4: Don't 'kill -9' the postmaster