题目6：MySQL----------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      |+----------+

题目解答：

select E1.Name from Employee as E1, Employee as E2 where E1.ManagerId = E2.Id and E1.Salary > E2.Salary

select a.Name   from Employee a,Employee b  where a.ManagerId = b.Id and a.Salary > b.Salary;