mysql 索引 優化 面試

mysql 索引 優化 面試題目：mysql 問如何優化下面的Mysql SQL語句？面試 select * from employee where employee.deptName in ( "departA", "departB", "departC") and tbl.locationID = 3 and tbl.level > 5;sql 思路：優化 1:  確定要創建二級聯合索引： i

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