SQL Server 2008 - 與兩個條件都匹配的查詢

Question

我試圖找到客戶（客戶ID）在剩下的幾周內同時擁有1和4的情況。我使用下面的查詢：

SELECT o.CustomerID, oi.RemainingWeeks 
FROM Orders o INNER JOIN 
     OrderItems oi ON o.OrderID = oi.OrderID 
WHERE (oi.OrderItemStatusID = 1) AND (oi.RemainingWeeks IN (1, 4)) 
ORDER BY o.CustomerID, oi.RemainingWeeks 

此發現誰剩餘數週或4對而不是那些有都有1客戶。我是否需要修改我的加入來完成此項工作？

謝謝！

Answer 1

這是一個relational division問題。通過聚集來解決這個問題的方法是

SELECT o.CustomerID 
FROM Orders o INNER JOIN 
     OrderItems oi ON o.OrderID = oi.OrderID 
WHERE (oi.OrderItemStatusID = 1) AND (oi.RemainingWeeks IN (1, 4)) 
GROUP BY o.CustomerID 
HAVING COUNT(DISTINCT oi.RemainingWeeks) = 2 
ORDER BY o.CustomerID 

Answer 2

要認識到的關鍵是，從OrderItems永遠不會有一個行，其餘的ReWiningWeeks等於1和4.因此，您需要以某種方式涉及多行。你可能會通過聚集實現這一點，或者只是進行第二聯接：

SELECT o.CustomerID, oi1.RemainingWeeks,oi2.RemainingWeeks 
FROM Orders o INNER JOIN 
     OrderItems oi1 ON o.OrderID = oi1.OrderID INNER JOIN 
     OrderItems oi2 ON o.OrderID = oi2.OrderID 
WHERE (oi1.OrderItemStatusID = 1) AND (oi1.RemainingWeeks =1) AND 
     (oi2.OrderItemStatusID = 1) AND (oi2.RemainingWeeks =4) 
ORDER BY 
    o.CustomerID, oi1.RemainingWeeks,oi2.RemainingWeeks