mysql 索引 优化 面试

mysql 索引 优化 面试题目：mysql 问如何优化下面的Mysql SQL语句？面试 select * from employee where employee.deptName in ( "departA", "departB", "departC") and tbl.locationID = 3 and tbl.level > 5;sql 思路：优化 1:  确定要创建二级联合索引： i

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