配置单元表与计数连接

Question

假定有两个表user和comments。下面是每个表中的字段，

用户：

userid
username

评论：

commentID
commentDescription
userid

编写查询以查找评论多于2条的用户

o / p文件：

userid
username
commentDescription

Answer 1

select u.userid,
       u.username,
       c.commentDescription 
  from user u
       inner join (select c.userid, c.commentDescription, 
                          count(*) over(partition by userid) cnt
                     from comments c
                  ) c 
        on u.userid=c.userid and c.cnt>2;