Question

我已经尝试了几个小时，但我想不出任何东西，因为存在只返回布尔值，每次我尝试使用存在时，我要么取回整个结果列表，要么没有。

以下代码返回了我想要的结果。

 SELECT  DISTINCT Clients.Clients_Code

 FROM         Account 

 INNER JOIN Clients ON Account.Account_Number = Clients.Account_Number 
 INNER JOIN Credit_Card ON Account.Account_Number = Credit_Card.Account_Number 
 INNER JOIN Transactions ON Credit_Card.Credit_Number = Transactions.Credit_Number 
 INNER JOIN Transactions AS Transactions_1 ON Credit_Card.Credit_Number = Transactions_1.Credit_Number 
 INNER JOIN Transactions AS Transactions_2 ON Credit_Card.Credit_Number = Transactions_2.Credit_Number 
 INNER JOIN Transactions AS Transactions_3 ON Credit_Card.Credit_Number = Transactions_3.Credit_Number

 WHERE (Transactions_3.Store_Code = '7182') 
 AND   (Transactions_2.Store_Code = '2019') 
 AND   (Transactions_1.Store_Code = '3121')

感谢您的回应和特别是BENJAMIN。他的回应完美无缺

Answer 1

根据我从您的详细信息中得知，您正在尝试找到在三个不同商店使用相同信用卡的客户。以下查询将提供相同的结果。

SELECT Clients.Clients_Code
FROM Clients c
INNER JOIN Credit_Card cc ON cc.Account_Number = c.Account_Number
Where Exists(select * from Tranctions t with (nolock) where t.Store_Code = '7182' and t.Credit_Number = cc.Credit_Number) 
AND Exists(select * from Tranctions t with (nolock) where t.Store_Code = '2019' and t.Credit_Number = cc.Credit_Number) 
AND Exists(select * from Tranctions t with (nolock) where t.Store_Code = '3121' and t.Credit_Number = cc.Credit_Number)

另一种选择是：

SELECT Clients.Clients_Code
FROM Clients c
INNER JOIN Credit_Card cc ON cc.Account_Number = c.Account_Number
Where (select count(*) from Tranctions t with (nolock) where t.Store_Code in ('7182', '2019','3121') and t.Credit_Number = cc.Credit_Number) =3

Answer 2

我怀疑你甚至需要账户表。

这有用吗？

SELECT DISTINCT Clients.Clients_Code FROM Clients 
INNER JOIN Credit_Card on Clients.Account_Number = Credit_Card.Account_Number 
WHERE EXISTS ( 
    SELECT null FROM Transactions 
    WHERE Transactions.Credit_Number = Credit_Card.Credit_Number
    AND Transactions.Store_Code in ('7182','2019','3121')
)

Answer 3

我不确定我完全理解你的问题。您是否询问该查询如何返回布尔值而不是实际记录？如果是这样的话：

IF EXISTS (SELECT DISTINCT Clients.Clients_Code
            FROM Account 
            INNER JOIN Clients 
              ON Account.Account_Number = Clients.Account_Number 
            INNER JOIN Credit_Card 
              ON Account.Account_Number = Credit_Card.Account_Number 
            INNER JOIN Transactions 
              ON Credit_Card.Credit_Number = Transactions.Credit_Number 
            INNER JOIN Transactions AS Transactions_1 
              ON Credit_Card.Credit_Number = Transactions_1.Credit_Number 
            INNER JOIN Transactions AS Transactions_2 
              ON Credit_Card.Credit_Number = Transactions_2.Credit_Number 
            INNER JOIN Transactions AS Transactions_3 
              ON Credit_Card.Credit_Number = Transactions_3.Credit_Number
            WHERE (Transactions_3.Store_Code = '7182') 
              AND (Transactions_2.Store_Code = '2019') 
              AND (Transactions_1.Store_Code = '3121'))
   SELECT 1 --True
ELSE
   SELECT 0 --False

如果那不是你想要完成的，请你澄清一下你的问题吗？

Answer 4

您的查询是......奇怪。

我认为您可以使用此查询获得相同的结果：

SELECT DISTINCT c.Clients_Code
FROM Account AS a
INNER JOIN Clients AS c
    ON a.Account_Number = c.Account_Number
INNER JOIN Credit_Card AS cc
    ON a.Account_Number = cc.Account_Number
INNER JOIN Transactions AS t
    ON cc.Credit_Number = t0.Credit_Number
WHERE t.Store_Code IN ('7182', '2019', '3121')

如果您想知道该查询是否存在任何结果，那么您只想将整个事物包装在EXISTS（[above_query]）中。

如何修改以下代码以使“exists”具有相同的结果？（SQL）

4 个答案: