SQL面试50题-42

42、查询每门功成绩最好的前两名（同22和25题）

SELECT k.s_id,k.c_id,k.s_score,k.ranking
FROM 
(SELECT s_id, c_id,s_score,
ROW_NUMBER() OVER (PARTITION BY c_id ORDER BY s_score DESC) ranking
 FROM Score s) k
WHERE k.ranking IN (1,2)
ORDER BY k.c_id,k.ranking