select S1.emp_no,(S1.salary-S2.salary) growth 
FROM 
(SELECT emp_no,salary
FROM salaries
WHERE to_date="9999-01-01") S1--先查询当前在职员工的工资
JOIN 
(SELECT s.emp_no,s.salary
FROM salaries s
JOIN employees e on e.emp_no=s.emp_no
and e.hire_date =s.from_date) S2--再查询员工入职日期的工资
on S1.emp_no =S2.emp_no  当前在职员工=之前员工入职的编号
order by growth 对涨幅进行升序排序