select g1.id, a.name, g1.score
from grade as g1
inner join language as a
on g1.language_id=a.id
where (
    select count(distinct g2.score)
    from grade as g2
    where g1.language_id=g2.language_id
    and g2.score>=g1.score
)<=2
order by a.name asc, g1.score desc, g1.id asc
# 使用where子查询：思想与内连接类似，不过也是一种思路。我们可以知道的是，一般可以使用where子查询的题目，同样可以使用内连接代替
# 
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三种解题方式：