* Jay Sprenkle <[EMAIL PROTECTED]> [2006-07-11 20:15]: > On 7/11/06, A. Pagaltzis <[EMAIL PROTECTED]> wrote: > >* Jay Sprenkle <[EMAIL PROTECTED]> [2006-07-10 17:30]: > >> // - Use SQL Joins instead of using sub-queries > > > >Not so fast there. I have accelerated queries by several 100 > >percent by turning joins into subqueries. On other occasions I > >did so by turning subqueries into joins. The performance of > >joins vs subqueries in any non-trivial query depends on a > >*lot* of variables. You can't just say "use this one" or "use > >the other" as a blanket statement. > > I just did the test of that one. All things being equal I saw > only a 1%-4% difference between the performance of the two > variants. I don't think thats enough to even be worth looking > at.
Let me guess: you tested trivial subqueries but not correlated ones? Regards, -- Aristotle Pagaltzis // <http://plasmasturm.org/>
