sql 面试题开窗函数row_number() over(partition by ... 分组 order by ...排序) as rn-CFANZ编程社区

表结构：

sql 面试题开窗函数row_number() over(partition by ... 分组 order by ...排序) as rn_数据

问题：求出每个班前三成绩的人姓名班级和排名

-- 解析，开窗函数， over（partition by 分组列1，分组列2 order by 排序列）as 排名

第一阶段全部数据排名：

sql 面试题开窗函数row_number() over(partition by ... 分组 order by ...排序) as rn_数据_02

第二阶段筛选排名

SELECT
  rn ,
  score,
  class,
  sname
from
  (
  SELECT
    *,
    ROW_NUMBER()
  OVER(PARTITION by
  class
  order by
    score desc 
  ) rn
  from
    std_score 
)t
where
  t.rn <= 3
  ;

　结果：

sql 面试题开窗函数row_number() over(partition by ... 分组 order by ...排序) as rn_数据_03