引用內部聯接中的不同表中的一列選擇

Question

我試圖加入到內部查詢中，該查詢使結果由另一個表中的值進行過濾，因此我可以選擇最上面的結果並使用值在我的主選擇語句中多次，但我得到的錯誤如下：

無法綁定多部分標識符「TessSCCall.Call_Num」。

請參見下面的代碼至今：

SELECT BestAppointmentOffer AS foo -- I'm using this lots of times in different fields 
     BestAppointmentOffer AS bar -- I'm using this lots of times in different fields 
    .... 
FROM TessSCEmploy 
INNER JOIN TessSCCall on TessSCEmploy.Employ_Num = TessSCCall.Call_Employ_Num 
INNER JOIN 
(
    SELECT TOP 1 dbo.Aqua_Midnight(AppointmentStartTime) 
    AS BestAppointmentOffer, CallNumber 
    FROM AQWEB.[360Tracking].dbo.AppointmentOffers 
    WHERE CallNumber = TessSCCall.Call_Num 
    ORDER BY AppointmentStartTime) AS Appointment 
on TessSCCall.Call_Num = Appointment.CallNumber 
where .... 

我怎樣才能得到這個工作，所以我可以從我的查詢中使用的值（即我目前正在試圖加入）在計算在多個領域，而不重複？

Answer 1

的最簡單的方法是使用CROSS APPLY，但由於您使用的是SQL Server 2000，因此您沒有該選項。您應該能夠使用聚合函數來獲取每個約會時間上的結果：

select BestAppointmentOffer AS foo -- I'm using this lots of times in different fields 
     BestAppointmentOffer AS bar -- I'm using this lots of times in different fields 
    .... 
from TessSCEmploy 
inner join TessSCCall 
    on TessSCEmploy.Employ_Num = TessSCCall.Call_Employ_Num 
INNER JOIN 
(
    SELECT min(dbo.Aqua_Midnight(AppointmentStartTime)) AS BestAppointmentOffer, 
    CallNumber 
    FROM AQWEB.[360Tracking].dbo.AppointmentOffers 
    GROUP BY CallNumber 
) AS Appointment 
    on TessSCCall.Call_Num = Appointment.CallNumber 
where .... 

Answer 2

你需要跨越適用於派生表

... 

TessSCEmploy inner join TessSCCall on TessSCEmploy.Employ_Num = TessSCCall.Call_Employ_Num 

CROSS APPLY 
(SELECT TOP 1 dbo.Aqua_Midnight(AppointmentStartTime) AS BestAppointmentOffer, CallNumber 
FROM AQWEB.[360Tracking].dbo.AppointmentOffers 
WHERE CallNumber = TessSCCall.Call_Num 
ORDER BY AppointmentStartTime) AS Appointment on TessSCCall.Call_Num = Appointment.CallNumber 

where .... 

CROSS應用相關聯的列是正確的結構，無論如何，這是一個「每個東西TOP 1」你在做什麼，