题解 | #查找在职员工自入职以来的薪水涨幅情况#

核心：最后记录时间的salary - 入职时间的salary

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