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Re: Why not use index
Posted by: Øystein Grøvlen
Date: November 10, 2015 10:35AM

Hi,

Are you sure it is not using the index? When I try a similar example, the Extra column of EXPLAIN says "Range checked for each record". This means that for each row of the left hand table, it will evaluate whether it is beneficial to use the index or not. (In this case, it will probably always be).

I agree that MySQL could be better at handling OR-expressions in ON-clauses. You can file a bug at bugs.mysql.com if you would like us to consider this feature.

Øystein Grøvlen,
Senior Principal Software Engineer,
MySQL Group, Oracle,
Trondheim, Norway

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