Question

我使用SSIS包每天更新我的内容。有数千个内容具有不同的审核ID，我想计算每个审核ID的前十个类别。在我意识到我应该为每个ModerationId计算它之前，我使用此查询来获取要更新的内容：

SELECT TOP 10 ModerationId, Category, COUNT(ContentSeqNum) AS Total FROM Content
WHERE Category IS NOT NULL
GROUP BY ModerationId, Category ORDER BY ModerationId, Total DESC

这是一种错误的方法，因为此查询计算所有数据的前十个类别，对于不同的ModerationId，它应该是不同的前十个类别。

如何更改此查询以计算每个ModerationId的前10个类别？

Answer 1

使用Window Function来计算categories的前十名Moderation ID。试试这个。

SELECT moderationid, 
       category, 
       total 
FROM   (SELECT Row_number() OVER (partition BY moderationid 
                   ORDER BY Count(contentseqnum)) Rn, 
               moderationid, 
               category, 
               Count(contentseqnum)               AS Total 
        FROM   content 
        WHERE  category IS NOT NULL 
        GROUP  BY moderationid, 
                  category) A 
WHERE  rn <= 10

Answer 2

试试这个：

SELECT TOP(10) ModerationId, Category, COUNT(ContentSeqNum) OVER(PARTITION BY ModerationId ORDER BY ModerationId) AS Total 
FROM Content
WHERE Category IS NOT NULL
ORDER BY Total DESC

Answer 3

使用Row_number（）函数

select * from
(
        select *, 
        row_number() over(partition by ModerationId order by ModerationId) as sno 
        from Content WHERE Category IS NOT NULL
) as t
where sno<=10

在http://beyondrelational.com/modules/2/blogs/70/posts/10845/return-top-n-rows.aspx

查找更多方法

计算SSIS中的前十个类别

3 个答案: