Question

我正在尝试加入一个内部查询，它的结果是由另一个表中的值过滤的，所以我可以选择最高结果并在我的主select语句中多次使用它，但是我收到如下错误：

无法绑定多部分标识符“TessSCCall.Call_Num”。

到目前为止，请参阅下面的代码：

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 ....

我怎样才能让它工作，所以我可以在多个字段的计算中使用我的查询中的值（我目前正在尝试加入），而不重复它？

Answer 1

最简单的方法是使用CROSS APPLY，但由于您使用的是SQL Server 2000，因此没有该选项。您应该能够使用聚合函数来获得每个约会时间的最高结果：

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

您需要CROSS APPLY来关联派生表中的列

...

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 APPLY对于你正在做的事情来说是正确的构造，这是一个“每件事的TOP 1”

引用内连接选择中不同表的列

2 个答案: