#薪水涨幅=当前薪资-入职薪资
#解题步骤：1.找出入职时的薪资 2.找出当前薪资 3.把前两步进行联结，将两次薪水相减
select e.emp_no,(t.salary-e.salary)as growth
from
(select a.emp_no,b.salary
from employees as a 
inner join salaries as b
on a.hire_date=b.from_date)as e 
inner join 
(select emp_no,salary,to_date
from salaries 
where to_date='9999-01-01')as t 
on e.emp_no=t.emp_no
order by growth