解法

select t1.id, t2.name, t1.score
from
  (select id, language_id, score, dense_rank() over (partition by language_id order by score desc) as ranks from 
  grade) t1,
  language t2
where 
  t1.ranks in (1,2)
  and t1.language_id = t2.id
  order by t2.name,t1.score desc, t1.id