###前面有一道中位数的题，参考其解法，对于正排序号大于等于总数/2且倒排序号大于等于总数/2则为中位数

select id,job,score,t_rank
from (
select id,job,score,count(score)over(partition by job )  as st
            ,row_number()over(partition by job order by score)   as s1
            ,row_number()over(partition by job order by score desc ) as t_rank
from grade
)t
where s1>=st/2 and t_rank >=st/2
order by 1