181. Employees Earning More Than Their Managers

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      |+----------+ 方法一：使用inner，效率更高

select a.Name AS  Employee  FROM Employee a inner join Employee  b ON(a.ManagerId =b.Id and a.Salary >b.Salary )

 

方法二：使用where

SELECT E.Name Employee    FROM Employee E ,Employee M    WHERE E.ManagerId=M.Id AND E.Salary>M.Salary;