题解 | #考试分数(三)#

窗口函数

select t.id,l.name,t.score 
FROM 
(select *,DENSE_RANK()over(partition by language_id order BY score desc ) dr
FROM grade) t JOIN language l on t.language_id=l.id
WHERE t.dr<=2
ORDER BY l.name,t.score desc,t.id