题解 | #查找在职员工自入职以来的薪水涨幅情况#

select
    a.emp_no emp_no,
    (b.salary - a.salary) growth
from
    (
        select
            e.emp_no emp_no,
            s.salary salary
        from
            employees e
            inner join salaries s on e.emp_no = s.emp_no
        where
            e.hire_date = s.from_date
    ) a
    inner join (
        select
            e.emp_no emp_no,
            s.salary salary
        from
            employees e
            inner join salaries s on e.emp_no = s.emp_no
        where
            s.to_date = '9999-01-01'
    ) b on a.emp_no = b.emp_no
    order by growth