【leetcode Database】181. Employees Earning More Than Their Managers
题目:
The Employee
table holds all employees including their managers. Every employee has an Id, and there is also a column for the manager Id.
+----+-------+--------+-----------+
| Id | Name | Salary | ManagerId |
+----+-------+--------+-----------+
| 1 | Joe | 70000 | 3 |
| 2 | Henry | 80000 | 4 |
| 3 | Sam | 60000 | NULL |
| 4 | Max | 90000 | NULL |
+----+-------+--------+-----------+
Given the Employee
table, write a SQL query that finds out employees who earn more than their managers. For the above table, Joe is the only employee who earns more than his manager.
+----------+
| Employee |
+----------+
| Joe |
+----------+
解析:本题可以使用自连接来做。声明Employee表的两个别名e1和e2,然后select e1的ManagerId字段与e2的Id字段相等,且e1的Salary大于e2的Salary。代码如下:
# Write your MySQL query statement below
SELECT e1.Name AS Employee FROM Employee AS e1,Employee AS e2 WHERE e1.ManagerId = e2.Id AND e1.Salary > e2.Salary;
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