SQL面试50题-19
题目链接：https://zhuanlan.zhihu.com/p/43289968
按各科成绩进行排序，并显示排名(重点row_number)
知识点：row_number()、rank()、dense_rank()
1.对课程进行分组的情况
SELECT s_id,c_id,s_score,
ROW_NUMBER() OVER (*PARTITION BY c_id *ORDER BY s_score DESC) AS ranking
FROM score
2.不对课程分组的情况
SELECT s_id,c_id,s_score,
ROW_NUMBER() OVER (ORDER BY s_score DESC) AS ranking
FROM score
