题解 | #查找在职员工自入职以来的薪水涨幅情况#
查找在职员工自入职以来的薪水涨幅情况
http://www.nowcoder.com/practice/fc7344ece7294b9e98401826b94c6ea5
首先通过employees表跟salaries链接找到在职员工的当前薪资（to_date= '9999-01-01'）其次再通过employees表链接salaries表找到在职员工的入职工资（hire_date= from_date）
最后用当前薪资-入职薪资结果就是涨幅情况：查询语句如下：
select e.emp_no ,(s1.salary - s2.salary) growth -- 涨幅情况
from employees e join salaries s1
on e.emp_no = s1.emp_no and s1.to_date = '9999-01-01' -- 当前薪资
join salaries s2 on e.emp_no = s2.emp_no and e.hire_date = s2.from_date -- 入职薪资
order by growth
from employees e join salaries s1
on e.emp_no = s1.emp_no and s1.to_date = '9999-01-01' -- 当前薪资
join salaries s2 on e.emp_no = s2.emp_no and e.hire_date = s2.from_date -- 入职薪资
order by growth
