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Comments on: Question 48: Why is query B faster than query A? http://mysql-qotd.casperia.net/archives/359 mysql 5.0/5.1 questions for learning purposes Fri, 06 Aug 2010 16:56:36 +0000 http://wordpress.org/?v=abc hourly 1 By: plogi http://mysql-qotd.casperia.net/archives/359/comment-page-1#comment-56 plogi Sun, 23 May 2010 19:29:12 +0000 http://mysql-qotd.casperia.net/?p=359#comment-56 <b> a b c   Sometimes it is necessary to force a certain join order, even tho mostly the optimizer figures it out just fine. In general MySQL will determine the best join order, but there are the following mechanisms to control it: <pre> - the STRAIGHT_JOIN syntax - the USE INDEX/FORCE INDEX clauses - using operations in the join to force later evaluation </pre> </b>
a b c
 
Sometimes it is necessary to force a certain join order, even tho mostly the optimizer figures it out just fine.
In general MySQL will determine the best join order, but there are the following mechanisms to control it:

- the STRAIGHT_JOIN syntax
- the USE INDEX/FORCE INDEX clauses
- using operations in the join to force later evaluation

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