Re: Best practices for using MySQL index

>> Point above about spread still applies, but if you >> can join index to index, the join goes a lot faster. (A primary key in >> MySQL >> is always indexed.) >> > How much is the *a lot*? Thanks. :) If it's a unique (including primary) key then orders of magnitude for millions of rows. If it's a non-unique key, it depends on how many distinct values there are. -- Postgresql & php tutorials http://www.designmagick.com/