[LeetCode]-DataBase-Employees Earning More Than Their Managers

Posted 2020-06-27 练子

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

要求：查询出表中工资比经理高的员工姓名

查询一：

CREATE TABLE `employee` (
`id` tinyint(3) unsigned DEFAULT NULL,
`e_name` varchar(20) DEFAULT NULL,
`salary` decimal(10,2) DEFAULT NULL,
`m_id` tinyint(3) unsigned DEFAULT NULL
) ENGINE=MyISAM DEFAULT CHARSET=utf8;

 

SELECT em1.e_name
FROM(SELECT id,e_name,salary,m_id FROM employee_1 WHERE m_id IS NOT NULL) em1
INNER JOIN employee_1 em2 ON em1.m_id=em2.id
WHERE em1.salary>em2.salary

查询二：

SELECT e1.e_name
FROM employee_1 e1
INNER JOIN employee_1 e2 ON e1.m_id=e2.id
WHERE e1.salary>e2.salary