Question

对于以下sql命令

select h.hacker_id
    ,h.name
    ,challenges_created
from hackers h
inner join (
    select hacker_id
        ,count(*) as challenges_created /* line 1 */
    from challenges
    group by hacker_id
    order by 2 desc
    ) tmp on h.hacker_id = tmp.hacker_id
order by challenges_created desc
    ,h.hacker_id;

到目前为止还不错

只要我尝试将max(count(*)) as maximum添加到第1行，就会出现错误：

不是单组组功能

这是它给出错误的代码：

select h.hacker_id
    ,h.name
    ,challenges_created
from hackers h
inner join (
    select hacker_id
        ,count(*) as challenges_created
        ,max(count(*)) as maximum
    from challenges
    group by hacker_id
    ) tmp on h.hacker_id = tmp.hacker_id
order by challenges_created desc
    ,h.hacker_id;

到目前为止，我基本上对获得最大数量即challenges created的最大数量感兴趣。

我是sql的新手，请帮助和帮助。提前致谢。是的，当然！我知道最近有很多这样的问题被问到，但没有一个符合我的情况，这就是为什么我要再问一次。

Answer 1

试试这个：

with x as (
  select h.hacker_id, h.name, count(*) challenges_created 
  from hackers h 
  inner join challenges on h.hacker_id = challenges.hacker_id
  group by h.hacker_id, h.name
)
select x.*, 
       (select max(challenges_created) from x) as "max"
from x
order by challenges_created desc, hacker_id;

Oracle - 不是单组组功能

1 个答案: