【牛客sql实战21】查找所有员工自入职以来的薪水涨幅情况

题目描述

查找所有员工自入职以来的薪水涨幅情况，给出员工编号emp_no以及其对应的薪水涨幅growth，并按照growth进行升序
（注:可能有employees表和salaries表里存在记录的员工，有对应的员工编号和涨薪记录，但是已经离职了，离职的员工salaries表的最新的to_date!=‘9999-01-01’，这样的数据不显示在查找结果里面）

CREATE TABLE `employees` (
`emp_no` int(11) NOT NULL,
`birth_date` date NOT NULL,
`first_name` varchar(14) NOT NULL,
`last_name` varchar(16) NOT NULL,
`gender` char(1) NOT NULL,
`hire_date` date NOT NULL, --  '入职时间'
PRIMARY KEY (`emp_no`));
CREATE TABLE `salaries` (
`emp_no` int(11) NOT NULL,
`salary` int(11) NOT NULL,
`from_date` date NOT NULL, --  '一条薪水记录开始时间'
`to_date` date NOT NULL, --  '一条薪水记录结束时间'
PRIMARY KEY (`emp_no`,`from_date`));

分析

# 查询当前工资，并查询入职时候的工资，再相减
select s1.emp_no,(s1.salary-s2.salary) as growth
from (select emp_no,salary from salaries
      where to_date='9999_01_01') as s1
inner join (select s.emp_no,s.salary from salaries as s 
           inner join employees as e
           on s.emp_no=e.emp_no and s.from_date=e.hire_date) as s2
where s1.emp_no=s2.emp_no
order by growth