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      |+----------+

题意：找出工人的工资比其上级工资高的工人

用时1693ms

select name from Employee as e1 where salary > (select salary  from Employee as e2 where e2.id = e1.managerid)

用连接查询用时1666ms

select e1.name from Employee as e1 inner join Employee as e2 on e1.managerid = e2.id and e1.salary > e2.salary;

用时1348ms

SELECT a.NAME FROM Employee a, Employee b WHERE a.ManagerId = b.Id AND a.Salary > b.Salary;