题解 | #查找在职员工自入职以来的薪水涨幅情况#

#重点：可能存在降薪的情况，所以最大工资-最小工资不一定是入职以来的涨幅。（一开始没想到，直接max-min了）
#自连接
select c.emp_noa as emp_no, (salary_b-salary_a) as growth
from
(
select a.emp_no as emp_noa,a.salary as salary_a,b.to_date as date,b.emp_no as emp_nob,b.salary as salary_b
from (salaries a) inner join salaries b
on a.emp_no = b.emp_no and a.from_date < b.from_date and b.to_date = '9999-01-01' and a.from_date in #员工在职  入职工资即招聘时的工资
(select hire_date
from employees)
) as c
order by growth asc