Question

我正在尝试按月创建一系列顶级R帖子的时间序列。来自SE数据资源管理器的年份使用this query。这是我写的查询：

select Id, Title, Score, year(CreationDate) as creation_year, 
  month(CreationDate) as creation_month from Posts pp  
  inner join(max(Score) as max_score, year(CreationDate) as creation_year, 
    month(CreationDate) as creation_month from Posts 
  group by year(CreationDate),  month(CreationDate)) grouped_pp 
  on pp.creation_year = grouped_pp.creation_year 
  and pp.creation_month = grouped_pp.creation_month
  and pp.Score = grouped_pp.max_score
  where tags = '<r>'

然而，这失败了，无益：

＆＃39;，＆＃39;附近的语法不正确。

不确定如何修复此查询。

Answer 1

您在select之后错过了join;

select 
    Id, 
    Title, 
    Score, 
    year(CreationDate) as creation_year, 
    month(CreationDate) as creation_month 
from Posts pp  
inner join (
    select
        max(Score) as max_score, 
        year(CreationDate) as creation_year, 
        month(CreationDate) as creation_month 
    from Posts 
    group by year(CreationDate),  month(CreationDate)
) grouped_pp 
on year(pp.CreationDate) = grouped_pp.creation_year 
and month(pp.CreationDate) = grouped_pp.creation_month
and pp.Score = grouped_pp.max_score
where tags = '<r>'

您必须将pp.creation_year修改为year(pp.CreationDate) [和month相同]才能使查询正常工作

要获得所需的结果，您可能需要使用另外两个表格，例如PostTags和tags;

select 
    Id, 
    Title, 
    Score, 
    creation_year, 
    creation_month
from (
    select
        p.Id,
        p.Title,
        p.Score,
        year(p.CreationDate) as creation_year,
        month(p.CreationDate) as creation_month,
        rank() over(partition by year(p.CreationDate), month(p.CreationDate) order by p.Score desc) rnk
    from Posts p 
    join PostTags pt on pt.postid = p.Id
    join tags t on t.id = pt.tagid
    where t.tagname  =  'r'
) x
where rnk  = 1
order by creation_year, creation_month

以下是link

SE数据资源管理器：按月和月份排名最高的R帖子的时间序列年

1 个答案: