Employee 表包含所有员工,他们的经理也属于员工。每个员工都有一个 Id,此外还有一列对应员工的经理的 Id。
+----+-------+--------+-----------+
| Id | Name | Salary | ManagerId |
+----+-------+--------+-----------+
| 1 | Joe | 70000 | 3 |
| 2 | Henry | 80000 | 4 |
| 3 | Sam | 60000 | NULL |
| 4 | Max | 90000 | NULL |
+----+-------+--------+-----------+
给定 Employee 表,编写一个 SQL 查询,该查询可以获取收入超过他们经理的员工的姓名。在上面的表格中,Joe
是唯一一个收入超过他的经理的员工。
+----------+
| Employee |
+----------+
| Joe |
+----------+
来源:力扣(LeetCode)
链接:https://leetcode-cn.com/problems/employees-earning-more-than-their-managers
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首先查出属性只为员工的人员
select * from Employee where ManagerId is NOT NULL
然后再以经理的ID左连接员工表
select A.Name AS Employee from (select * from Employee where ManagerId is NOT NULL) as A left join Employee B on A.ManagerId=B.Id
再加上条件员工的工资比经理的工资要大即为结果
select A.Name AS Employee from (select * from Employee where ManagerId is NOT NULL) as A left join Employee B on A.ManagerId=B.Id where A.Salary>B.Salary;