In addition to what others said... There is a lot more instruction both online and offline, but here is a brief example illustrating EXPLAIN:
http://www.experts-exchange.com/articles/Database/MySQL/3-Ways-to-Speed-Up-MySQL.html The docs can be a bit dense if you're not familiar with what you are looking for, but here it is for reference: http://dev.mysql.com/doc/refman/5.0/en/using-explain.html The first things you need to look at are the `type` and `ref`s columns. They will tell you what, if any, keys are used. Another thing to look for is any comments in the `Extra` column. If that has NULL, or 'filesort', or 'full scan' then you have some work to do. Finally, I took a glance at the slides in this page and they look informative, but I haven't watched the presentation. I will need to d/l it and watch it later. http://forge.mysql.com/wiki/Optimizing_Queries_with_Explain On Mon, Mar 22, 2010 at 10:27 AM, Rob Marscher <rmarsc...@beaffinitive.com>wrote: > On Mar 22, 2010, at 11:00 AM, Nicholas Hart wrote: > > I am looking to analyze and speed up some of my queries by adding any > necessary indexes. Is there a formula to follow in adding indexes to > multiple join queries? I have made some attempts using explain but am not > sure I understand it all that well. > > > > For example: > > $sql = "select dt1.*, d.* from > > driver d join > > (select `driver`, date(`leave`), sum(`points`) as pnts, > > sum(`xpnts`) as xpnts from check_head > > where date(`leave`) = '".$sdate."' > > group by `driver`) dt1 > > on dt1.driver = d.id_num where `store` = '".$userStore."' "; > >
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