创建sql变量并查询其他表

我试图查询一个表，并将结果放入一个变量中。使用变量结果，使用变量详细信息作为过滤器执行另一个select查询

到目前为止：

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

我收到一个错误：

子查询返回了多个值。当子查询在=、！=、=或者当子查询用作表达式时

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您的问题是多个存储具有相同的

ParentStoreID

，因此在查询时，您试图将多个值放入

INT

变量中

您可以尝试：

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

此查询应提供您想要的所有购买信息，这些信息来自

ParentStoreId=9

的所有商店

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有关的信息也可能对您有所帮助。

除非您特别希望在其他地方使用

@StoreIds

变量，否则您只需将

WHERE

子句修改为：

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

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Barry和Adam Wenger有最好的方法，但是为了直接解决错误，您可以确保在使用top 1修饰符设置变量时只得到一个结果。比如：

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

---

可以通过不同的方式完成：

使用子查询

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

使用联接操作

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

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谢谢你，巴里！我不知道我可以在WHERE中创建另一个select语句：(