SQL - 使用Selected列確定數據行數量？

Question

SELECT cust.Name, rec.ProductID, 
     CASE WHEN rec.IsPaid IS NULL THEN 0 ELSE 1 END  
FROM Customer AS [cust] 
LEFT JOIN Records AS [rec] 
ON cust.CustID = rec.CustID 

嗨，夥計們。我想知道有沒有辦法返回一行數據ONLY當isPaid是1？

表示如果IsPaid爲0，整行數據將不會被選中。

Answer 1

那麼首先你真的需要將rec.IsPaid返回爲0或1嗎？因爲您的查詢可以簡化爲：

SELECT cust.Name, rec.ProductID 
FROM Customer AS [cust] 
LEFT JOIN Records AS [rec] 
ON cust.CustID = rec.CustID 
WHERE rec.IsPaid IS NOT NULL;