需要查询以确定每个问题的附件数量

Question

我在 SQL 服务器中有一个数据库，该数据库具有三个表：问题、附件和请求者。我需要一个查询 returns "Issues" 和 "Attachments" 表中包含的所有列。下面列出的是我创建的查询，但它没有按预期工作：

SELECT A.*, 
       B.*, 
       SubQuery.attachmentcount 
FROM   [DB].[dbo].[issues] AS A 
       FULL OUTER JOIN [DB].[dbo].[requestors] AS B 
                    ON A.issue_id = B.issue_id, 
       (SELECT Count(attachments.attachment_id) AS AttachmentCount 
        FROM   issues 
               LEFT OUTER JOIN attachments 
                            ON issues.issue_id = attachments.issue_id 
        WHERE  attachments.attachment_status = 1 
        GROUP  BY issues.issue_id) AS SubQuery;

下面列出了描述三个表的图片：

关于如何修复我的查询有什么想法吗？

谢谢，

Answer 1

"I need a single query that returns all the columns contained in the "问题”和 "Attachments" 表”。基于这句话试试这个：

SELECT A.Issue_ID, I.Issue_Name,r.Name, COUNT(A.attachment_id) AS Count 
FROM Attachments as A 
INNER JOIN Issues I  on I.issue_id = A.issue_id 
INNER JOIN requestors as R on A.issue_id  = R.requestor_id
WHERE A.attachment_status = 1
GROUP BY A.Issue_ID, I.Issue_Name, r.Name
--Specify all columns by name (don't use *)

Answer 2

保持简单并尝试这个！

    SELECT i.Issue_ID, i.Issue_Name, COUNT(a.attachment_id) AS AttachmentCount 
    FROM attachments a JOIN
    issues i  ON 
    i.issue_id = a.issue_id 
    WHERE a.attachment_status = 1
    GROUP BY i.Issue_ID, i.Issue_Name

在 Select 列表 和 Group By Clause 中添加您的所需的列 ] 你已经 完成了 。

需要查询以确定每个问题的附件数量

Need query to determine number of attachments for each issue

tsql

sql-server

inner-join

outer-join

sql-server-2012

保持简单并尝试这个！