mysql 力扣，569.员工薪水中位数

569.员工薪水中位数
https://leetcode-cn.com/problems/median-employee-salary/

参考答案

# 先组内排序，命名为sc，这里用了库函数，也可以自己写
#这题的中位数是偶数个就是中间两个，奇数个就是中间一个，（题目要求）
#然后看where子句，三个分别是每个公司和如果是奇数个就拿中间一个，偶数个就拿个数除以2的，偶数个就拿个数除以2加1的
#然后根据公司和组内排名就把中无数拿出来了。

with sc as
    (select *,row_number() over(partition by Company  order by Salary ) 'rankx',
    count(Salary)over(partition by Company ) people
    from employee)
    
select Id, Company,Salary from sc
where (Company,rankx) in (
    select Company,floor((people+1)/2) 'rankx'
    from sc where people%2=1
    union 
    select Company,floor((people+1)/2) 'rankx'
    from sc where people%2=0
    union
    select Company,floor((people+1)/2)+1 'rankx'
    from sc where people%2=0)