题解 | 查找在职员工自入职以来的薪水涨幅情况

select
    t1.emp_no,
    (t2.salary - t1.salary) as growth
from
    (
        select
            e.emp_no,
            s.salary
        from
            employees e
            join salaries s on e.emp_no = s.emp_no
            and e.hire_date = s.from_date
    ) as t1
    join (
        select
            e.emp_no,
            s.salary
        from
            employees e
            join salaries s on e.emp_no = s.emp_no and s.to_date = '9999-01-01'
    ) as t2 on t1.emp_no = t2.emp_no
order by growth