mysql索引

参考文献来自https://www.cnblogs.com/morewindows0/p/9223671.html

下面为自己做的测试，记下来以防忘记

EXPLAIN select * from suoyin_test where c2='a1'

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EXPLAIN select * from suoyin_test where c2='a1' and c1='a1'

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EXPLAIN select * from suoyin_test where c1 like 'a1%' and c2='a1' 

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EXPLAIN select * from suoyin_test where c1 like 'a1%' and c3='a1' 

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EXPLAIN select * from suoyin_test where c1='a1%' and c2='a1' ORDER BY c3

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EXPLAIN select * from suoyin_test where c1='a1%' and c3='a1' ORDER BY c2

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