25. 获取员工其当前的薪水比其manager当前薪水还高的相关信息

题目描述

获取员工其当前的薪水比其manager当前薪水还高的相关信息，当前表示to_date='9999-01-01',
结果第一列给出员工的emp_no，
第二列给出其manager的manager_no，
第三列给出该员工当前的薪水emp_salary,
第四列给该员工对应的manager当前的薪水manager_salary
CREATE TABLE `dept_emp` (
`emp_no` int(11) NOT NULL,
`dept_no` char(4) NOT NULL,
`from_date` date NOT NULL,
`to_date` date NOT NULL,
PRIMARY KEY (`emp_no`,`dept_no`));
CREATE TABLE `dept_manager` (
`dept_no` char(4) NOT NULL,
`emp_no` int(11) NOT NULL,
`from_date` date NOT NULL,
`to_date` date NOT NULL,
PRIMARY KEY (`emp_no`,`dept_no`));
CREATE TABLE `salaries` (
`emp_no` int(11) NOT NULL,
`salary` int(11) NOT NULL,
`from_date` date NOT NULL,
`to_date` date NOT NULL,
PRIMARY KEY (`emp_no`,`from_date`));

输入描述:

无

输出描述:

emp_no	manager_no	emp_salary	manager_salary
10001	10002	88958	72527
10009	10010	95409	94409

SELECT
	d1.emp_no AS emp_no,
	d2.emp_no AS manager_no,
	d1.salary AS emp_salary,
	d2.salary AS manager_salary
FROM
	(
		dept_emp d
		INNER JOIN salaries s ON d.emp_no = s.emp_no
		AND s.to_date = '9999-01-01'
	) AS d1,
	(
		dept_manager m
		INNER JOIN salaries s ON m.emp_no = s.emp_no
		AND s.to_date = '9999-01-01'
	) AS d2
WHERE
	d1.salary > d2.salary
AND d1.dept_no = d2.dept_no;