题解 | #查找在职员工自入职以来的薪水涨幅情况#

select a.emp_no,(now_salary-ago_salary) as growth
from
(
    ##入职员工对应的工资
    select a.emp_no,salary as ago_salary
    from employees a
    join salaries b on a.emp_no =b.emp_no and hire_date =from_date 
)a
join 
(
    ##当前工资
    select emp_no ,salary as now_salary
    from salaries
    where to_date='9999-01-01'
)b on a.emp_no=b.emp_no
order by growth