正常情况下mysql的like模糊查询时索引是不会起作用的,但是有些条件下是可以用索引的,如左边固定,右单边模糊的时候
explain extended select * from users where email like '303578599%'
explain extended select * from users where email like '303%578599%'
如果起始就是模糊查询,就要全表扫描了
explain extended select * from users where email like '%303578599%'