sql - Put indexes on a table with lots of BOOL/TINYINT? -

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An old mentor once asked me to index things that you can call WHERE For use.

Should I put an index on BOOL / TINYINT ? In the table I am working in, one of them is significant amount, and often the results are filtered anywhere with 1-20 bullion conditions.

A condition in which an index can be useful on boolean fields (or other low cardinal fields) . If the values ​​are relatively less than one (for example, 10 TRUE values ​​out of ten million) and if you are searching for those values ​​quite a few times then an index would be useful.


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