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Re: why left join can not use unique index?
Posted by: Rick James
Date: December 15, 2015 11:08AM

An index is a "table" organized based on the declared Collation. Hence, the index is useless when you want to look up something in a different Collation.

In utf8_german2_ci, these are all equal: ae=Ä=Æ=ä=æ
But in utf8_bin, they are scattered around. 'ae' is between 'ad' and 'af'; the others are separately stored separately somewhere after 'z'.

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h h
December 07, 2015 08:30PM
h h
December 11, 2015 03:20AM
Re: why left join can not use unique index?
December 15, 2015 11:08AM

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