創建一個sql變量並查詢其他表格

Question

我想查詢一個表格並將結果導入變量。使用變量結果做另一個選擇使用變量細節作爲過濾器的查詢。

到目前爲止：

DECLARE @storeIds int  
SET @storeIds = (SELECT StoreID FROM Store WHERE ParentStoreID=9) 

--print @storeIds 

SELECT c.FirstName, c.LastName, c.CustomerId, r.StoreID 
FROM Consumer AS c 
    INNER JOIN Purchases AS r ON c.CustomerId= r.CustomerId 
WHERE r.StoreID = @storeIds 
    -- (r.StoreID = 9) OR 
    -- (r.StoreID = 10) OR 
    -- (r.StoreID = 11) 
GROUP BY c.FirstName, c.LastName, c.CustomerId, r.StoreID 
ORDER BY c.FirstName 

我得到一個錯誤：

Subquery returned more than 1 value. This is not permitted when the subquery follows =, !=, <, <= , >, >= or when the subquery is used as an expression.

Answer 1

除非你特別想在其他地方的@StoreIds變量，你可以只修改你的WHERE子句：

WHERE r.StoreID IN (SELECT StoreID FROM Store WHERE ParentStoreID = 9) 

Answer 2

你的問題是，多個商店具有相同的ParentStoreID，所以當您查詢，您正試圖把多值寫入INT變量。

你可以看一下嘗試：

SELECT c.FirstName, c.LastName, c.CustomerId, p.StoreID 
FROM Consumer AS c 
INNER JOIN Purchases AS p ON c.CustomerId = p.CustomerId 
INNER JOIN Store AS s ON p.StoreId = s.StoreId 
WHERE s.ParentStoreID = 9 
GROUP BY c.FirstName, c.LastName, c.CustomerId, r.StoreID 
ORDER BY c.FirstName 

該查詢應該給你你想要的所有采購，從所有的商店與ParentStoreId = 9。

關於JOINS的信息可能對您有幫助。

Answer 3

巴里和亞當·溫格擁有最好的辦法，但要直接解決了錯誤，你能保證你在使用頂部1修改器設置變量的同時得到正好一個結果。像：

DECLARE @storeIds int  
SET @storeIds = (SELECT top 1 StoreID FROM Store WHERE ParentStoreID=9) 

Answer 4

可以用不同的方式來完成：

1. 使用子查詢

   SELECT c.FirstName, c.LastName, c.CustomerId, r.StoreID 
   FROM Consumer AS c 
       INNER JOIN Purchases AS r ON c.CustomerId= r.CustomerId 
   WHERE r.StoreID = (SELECT StoreID FROM Store WHERE ParentStoreID=9) 
   GROUP BY c.FirstName, c.LastName, c.CustomerId, r.StoreID 
   ORDER BY c.FirstName 
   

2. 使用連接操作

   SELECT c.FirstName, c.LastName, c.CustomerId, r.StoreID 
   FROM Consumer AS c 
       INNER JOIN Purchases AS r ON c.CustomerId= r.CustomerId 
       INNER JOIN (SELECT StoreID FROM Store WHERE ParentStoreID=9) AS s(StoreID) 
        ON r.StoreID = s.StoreID 
   GROUP BY c.FirstName, c.LastName, c.CustomerId, r.StoreID 
   ORDER BY c.FirstName