SQL COUNT無法與將SELECT查詢嵌套在LEFT外部聯接中一起使用

Question

我需要一個Count才能在我的主選擇中使用原始問題希望通過INTO現有的工作查詢中的Group by添加一個Count查詢

--- this join works ---
LEFT OUTER JOIN
WorkItemAssignedToUserFactvw AS IATUFact 
ON 
WI.WorkItemDimKey = IATUFact.WorkItemDimKey 
AND IATUFact.DeletedDate IS NULL 
--- this part below is in both queries ---
LEFT OUTER JOIN
UserDimvw AS AssignedToUser 
ON 
IATUFact.WorkItemAssignedToUser_UserDimKey = AssignedToUser.UserDimKey 

如果我將查詢更改為具有選擇語句的Left外部聯接，那么我將遇到錯誤

LEFT OUTER JOIN
(
    SELECT
        WorkItemDimKey--,
        DateKey,
        --COUNT(WorkItemAssignedToUser_UserDimKey) AS Assignments
    FROM
        WorkItemAssignedToUserFactvw
    WHERE
        DeletedDate IS NULL
    GROUP BY
        WorkItemDimKey--,
        --DateKey
)
     IATUFact
        ON  WI.WorkItemDimKey = IATUFact.WorkItemDimKey

--- same query join as before except now it had an error 
LEFT OUTER JOIN
UserDimvw AS AssignedToUser 
ON 
IATUFact.WorkItemAssignedToUser_UserDimKey = AssignedToUser.UserDimKey 

錯誤：

消息207，級別16，狀態1，行292無效的列名稱'WorkItemAssignedToUser_UserDimKey'。

Answer 1

在您的SELECT中“使用”應該使用WorkItemAssignedToUser_UserDimKey來解決此問題，並將其添加到組中。

LEFT OUTER JOIN
(
    SELECT
        WorkItemAssignedToUser_UserDimKey,
        WorkItemDimKey,
        DateKey,
        COUNT(WorkItemAssignedToUser_UserDimKey) AS Assignments
    FROM
        WorkItemAssignedToUserFactvw
    WHERE
        DeletedDate IS NULL
    GROUP BY
        WorkItemAssignedToUser_UserDimKey,
        WorkItemDimKey,
        DateKey
)
     IATUFact
        ON  WI.WorkItemDimKey = IATUFact.WorkItemDimKey

--- same query join as before except now it had an error 
LEFT OUTER JOIN
UserDimvw AS AssignedToUser 
ON 
IATUFact.WorkItemAssignedToUser_UserDimKey = AssignedToUser.UserDimKey 

也許您已經注釋掉了東西，看看是否是問題所在？