【Leetcode】181. Employees Earning More Than Their Managers （Easy）

Employees Earning More Than Their Managers （Easy）"/>

【Leetcode】181. Employees Earning More Than Their Managers （Easy）

1.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      |
+----------+

2.思路

复制Employee得到一张新表Employee_new，两张表内连接，保证条件：

①Employee的ManagerId和 Employee_new的Id一致；

②Employee的Salary高于Employee_new的Salary.

3.算法

select Employee.Name as Employee
from Employee join (Employee as Employee_new)
where Employee.ManagerId = Employee_new.Id and Employee.Salary>Employee_new.Salary