Question

我有一个查询，它从受影响的表和支持表中查找应用程序。第三个表包含了我需要查询的更多项目信息。其中一个是状态字段。我想为该Project表添加一个连接，并且仅当状态显示为In Progress时才返回结果。这就是我到目前为止所做的：

数据和列的示例

以下申请信息

Appid ProjectId
 197   251

以下的项目信息栏

ProjectID ProjectName ImplementationDate Status

   select AppId                   = a.AppId,
   ApplicationName         = a.ApplicationName 

 from      Applications           a
 left join ( select AppId = t.AppId ,
               Cnt   = count(*)
        from ImpactedApplications t
        group by t.AppId
      ) ia on ia.AppId = a.AppId
 left join ( select AppId = t.AppId ,
               Cnt   = count(*)
        from SupportingApplications t
        group by t.AppId
      ) sa on sa.AppId = a.AppId
      where sa.Cnt > 0 OR ia.Cnt > 0 ORDER BY ApplicationName ASC

Answer 1

CTE方法

WITH CTE（appid，ApplicationName，ProjectId）如（

    select AppId                   = a.AppId,
       ApplicationName         = a.ApplicationName, 
       ProjectId               = a.ProjectId
     from      Applications           a
     left join ( select AppId = t.AppId 
                   Cnt   = count(*)
            from ImpactedApplications t
            group by t.AppId
          ) ia on ia.AppId = a.AppId
     left join ( select AppId = t.AppId 
                   Cnt   = count(*)
            from SupportingApplications t
            group by t.AppId
          ) sa on sa.AppId = a.AppId
          where sa.Cnt > 0 OR ia.Cnt > 0 ORDER BY ApplicationName ASC

)
select * from CTE C
INNER JOIN Porject P
on C.ProjectId = P.ProjectID
and P.Status = 'InProgress'

UNION可能会在这里工作

SELECT ApplicationName , P.*
FROM Applications A
INNER JOIN ImpactedApplications IA
on A.AppId = IA.AppId
INNER JOIN Project P
on IA.ProjectId = P.ProjectID
AND P.Status ='InProgress'
UNION
SELECT ApplicationName , P.*
FROM Applications A
INNER JOIN SupportingApplications SA
on A.AppId = SA.AppId
INNER JOIN Project P
on IA.ProjectId = P.ProjectID
AND P.Status ='InProgress'
order by ApplicationName ASC

Answer 2

如果我对现有代码没有错，你需要在两个表上基于projectid将项目表与应用程序表连接起来，只需要获取status = InProgress的记录。

select AppId                   = a.AppId,
   ApplicationName         = a.ApplicationName, 
   p.*
 from      Applications           a
 left join ( select AppId = t.AppId ,
               Cnt   = count(*)
        from ImpactedApplications t
        group by t.AppId
      ) ia on ia.AppId = a.AppId
 left join ( select AppId = t.AppId ,
               Cnt   = count(*)
        from SupportingApplications t
        group by t.AppId
      ) sa on sa.AppId = a.AppId
 join project p on a.projectid=p.projectid
      where (sa.Cnt > 0 OR ia.Cnt > 0 )
            and p.status='InProgress'
ORDER BY ApplicationName ASC

将状态检查添加到多个表查询

2 个答案: