题解 | #查找在职员工自入职以来的薪水涨幅情况#

select e.emp_no,(s2-s1) as growth
from employees as e
inner join 
(select e.emp_no,s.salary as s2 from employees as e
inner join salaries as s
on e.emp_no = s.emp_no
where  s.to_date = "9999-01-01")t1
on t1.emp_no = e.emp_no
inner join 
(select e.emp_no,s.salary as s1 from employees as e
inner join salaries as s
on e.emp_no = s.emp_no
where e.hire_date = s.from_date)t2
on t2.emp_no = e.emp_no
group by growth

1.查找出每个员工入职时的工资
2.查找出每个员工当前工资
3.用当前工资-入职时工资得到工资涨幅
4.按照工资涨幅排序