Mark wrote: >> select user_id from t_users where user_id = (select max(user_id) from >> t_users) >> > > It should be noted that that is the absolute 100% WRONG way to do it. If > your site has any concurrency, you will almost certainly get the wrong > user.
I agree 100% that it is 100% wrong, but just to point out something blindingly obvious: it is also incredibly inefficient at being wrong!! The sub-select selects the maximum user_id in the table. Fair enough. This user_id is then fed into a statement that just returns that value via a pointless lookup. SELECT user_id from t_users WHERE user_id = 42; Hmmmmm I wonder what user_id I'll get from that select.... Col. -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
