select a.emp_no,(b.salary - a.salary) growth
from
(select e.emp_no,s.salary
from employees e left join salaries s on e.emp_no=s.emp_no
where e.hire_date = s.from_date) a
--初始薪资
left join
--每次薪资
(select emp_no,salary,to_date from salaries) b
on a.emp_no = b.emp_no
where b.to_date="9999-01-01" --筛选最后薪资
order by growth