Re: Query not using full index
Posted by:
Jay Pipes
Date: July 30, 2005 08:16AM
The queries are not equivalent because of the SELECT *.
In the first, you are only returning results from datatable. In the second, all the data fields from both fktable1 and fktable2 tables are returned. If you remove the SELECT * and specify only the datatable fields you wish to return, you should notice that MySQL will "optimize away" the fktable1 and fktable2 results from the second EXPLAIN.
Jay Pipes
Community Relations Manager, North America, MySQL Inc.
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Re: Query not using full index
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