On 24 Dec 2011, at 14:15, thebigdog wrote: > On 12/23/11 4:48 PM, Wade Preston Shearer wrote: >> Am I correct in my understanding that the right side of an OR statement in an >> MySQL query doesn't get evaluated unless the left side fails? I have a query >> where the left-side case of an OR occurs often and produces an efficient >> query and the right-side happens only occasionally and produces a slower, >> less efficient query. If the query always checks both but only uses the left >> if it is true, then I'd be better served to move it into two queries. If it >> only checks the right-side condition if the left-side fails though, then >> keeping it in one makes sense. > > For queries like this you really need to check out the explain plan and see > what > mysql is doing with your select statement. This is one of the best ways to > determine when mysql will use indexes or not on your data.
To make sure I was clear, my OR is in the WHERE. _______________________________________________ UPHPU mailing list [email protected] http://uphpu.org/mailman/listinfo/uphpu IRC: #uphpu on irc.freenode.net
