故障与嵌套查询

Question

我有这个疑问，其完美的作品：

SELECT * 
FROM Customer 
WHERE SacCode IN 
(
    SELECT SacCode 
    FROM SacCode 
    WHERE ResellerCorporateID = 392 
    ORDER BY SacCode 
) 
AND CustomerID IN 
(
    SELECT CxID 
    FROM CustAppointments 
    WHERE AppRoomID IN 
    (
     SELECT AppRoomID 
     FROM ClinicRooms 
     WHERE ClinID IN 
     (
      SELECT ClinID 
      FROM AppClinics 
      WHERE ClinDate >='20090101' 
      AND ClinDate <='20091119' 
     ) 
    ) 
) 

不过，我需要看到ClinDate的值（最后一个嵌套查询里面）...

我该怎么办它？

谢谢。

Answer 1

我会用加入重写查询。然后，您可以访问任何连接的表中的任何数据。

例如，你可以重写查询是这样的：

SELECT c.*, ac.ClinDate 
FROM Customer c 
    JOIN SacCode sc ON sc.SacCode = c.SacCode 
    JOIN CustAppointments ca ON ca.CustomerID = c.CustomerID 
    JOIN ClinicRooms cr ON cr.AppRoomID = ca.AppRoomID 
    JOIN AppClinic ac ON ac.ClinID = cr.ClinID 
WHERE ac.ClinDate >='20090101' 
    AND ac.ClinDate <='20091119' 
    AND sc.ResellerCorporateID = 392 

Answer 2

想我会在FROM语句中使用派生表而不是3深层嵌套查询，将允许您访问值，并将更好地看起来很好。

Answer 3

您需要将子查询复制到FROM子句或使用JOIN重写查询。

Answer 4

它应该是这个样子：

SELECT c.*, a.ClinDate 

FROM Customer c 

inner join CustAppointments ca 
inner join ClinicRooms cr 
inner join AppClinics a 

where c.SacCode IN 
(
    SELECT SacCode 
    FROM SacCode 
    WHERE ResellerCorporateID = 392 
    ORDER BY SacCode 
) 

and c.CustomerID = ca.CxID 
and ca.AppRoomID = cr.AppRoomID 
and cr.ClinID = a.ClinID 

and a.ClinDate >='20090101' 
and a.ClinDate <='20091119'