查找所有员工自入职以来的薪水涨幅情况（难）

题目描述

查找所有员工自入职以来的薪水涨幅情况，给出员工编号emp_noy以及其对应的薪水涨幅growth，并按照growth进行升序
CREATE TABLE `employees` (
`emp_no` int(11) NOT NULL,
`birth_date` date NOT NULL,
`first_name` varchar(14) NOT NULL,
`last_name` varchar(16) NOT NULL,
`gender` char(1) NOT NULL,
`hire_date` date NOT NULL,
PRIMARY KEY (`emp_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	growth
10011	0
省略	省略
10010	54496
10004	34003

代码：

select de.emp_no,(de.salary-ds.salary) as growth
from (select d.emp_no,d.salary from employees as e left join salaries as d on d.emp_no = e.emp_no where d.to_date = '9999-01-01' ) as de
inner join (select d.emp_no,d.salary from employees as e left join salaries as d on d.emp_no = e.emp_no where d.from_date = e.hire_date) as ds
on ds.emp_no = de.emp_no
order by growth

或者是：

SELECT sCurrent.emp_no, (sCurrent.salary-sStart.salary) AS growth
FROM (SELECT s.emp_no, s.salary FROM employees e, salaries s WHERE e.emp_no = s.emp_no AND s.to_date = '9999-01-01') AS sCurrent,
(SELECT s.emp_no, s.salary FROM employees e, salaries s WHERE e.emp_no = s.emp_no AND s.from_date = e.hire_date) AS sStart
WHERE sCurrent.emp_no = sStart.emp_no
ORDER BY growth