知识点

1. 首先原表上加一列排名，因为要的是中位数只会有一个或者两个所以窗口函数排序使用row_number，题目要求是最大的是第一所以order by 使用降序排序。
2. 再加上各岗位的中位数列，因为中位数有一个或两个所以需要两列。floor()向下取整，ceiling()向上取整
3. 中位数就是排名在两个数直接的数

代码

select g1.id, g1.job, g1.score, g1.r as t_rank
from (
      select *,
      row_number() over(partition by job order by score desc) as r
      from grade
      ) as g1
join (
      select job,
      floor((count(id)+1)/2) as a1,
      ceiling((count(id)+1)/2) as a2
      from grade
      group by job
      ) as g2
on g1.job = g2.job
where g1.r between a1 and a2
order by g1.id