h...@tbbs.net wrote: > >>>> 2011/05/12 15:15 +0200, misiaq >>>> > h...@tbbs.net wrote: > (...) > > > > Is the optimizer so clever as to set that test outside the expression, and > > only then evaluate it when "houmuch" and "SharePrice" are not equal? > > > > > > Try it yourself: > mysql > explain extended select * from table1; > > and then > mysql > show warnings; > > You will see the optimized query. > > http://dev.mysql.com/doc/refman/5.0/en/explain.html > <<<<<<<< > Not much of an explanation of "EXPLAIN"--and this command is mostly about > indexing and joining, in SQL of course of immens importance, and, to be sure, > finding "houmuch" in my query costs JOINing and SUMming, but I see nothing > relevant to my question. On the other hand, maybe finding "houmuch" costs so > much more than the rest of the expression that it does not matter. > > In any case, there is here no answer to my question. > >
You're right about explain. That is why I suggested to use explain EXTENDED and then SHOW WARNINGS. Second query will show you the optimizer output. As far as I understand - that was the par of your question. Regards, m -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/mysql?unsub=arch...@jab.org
