Question

我是学习SQL的初学者。我有2张桌子。尝试以最少的交易金额获得客户的名字和姓氏-仅那一行。一整天都在尝试不同的代码，但是一无所获。

表1：订单

Customer_Id  TxnDate     Amount
-------------------------------
4001         21-Aug-18   245.99
4002         30-Jan-18    49.99
4003         15-Apr-17   204.87
4001         18-Dec-18   130.88
4004         15-May-17   198.33
4006          4-Feb-17   783.65

表2：客户

Customer_Id  AcctOpenDate  CustomerFirstName  CustomerLastName
--------------------------------------------------------------
4001          7-Jan-16     John               Doe
4002         15-Apr-15     Ashley             Smith
4003         14-May-14     Carter             Jones
4004         17-Sep-16     Ika                Gaut
4005         18-Aug-14     Gray               Show
4006         25-Oct-15     Kathia             Kim

查询：

SELECT 
    C.CustomerFirstName, C.CustomerLastName, O.Amount 
FROM 
    Customers C 
WHERE 
    Amount = (SELECT MIN(Amount) FROM Orders) Leasttxnamt 
INNER JOIN 
    Customers C ON O.Customer_Id = C.Customer_Id;

当前产生的错误：

第15层状态1的第31行，消息102
'Leasttxnamt'附近的语法不正确

Answer 1

如果我的理解正确，您正在从“订单”表中查找客户明智的最低金额。如果这是正确的，则可以根据需要使用以下脚本-

这在大多数数据库中都是可行的。

SELECT C.CustomerFirstName, C.CustomerLastName, MIN(Amount) min_amount
FROM Customers C 
LEFT JOIN Orders O ON O.Customer_Id = C.Customer_Id
GROUP BY C.CustomerFirstName, C.CustomerLastNam

Answer 2

尝试以下查询：

SELECT Customers.CustomerFirstName ,Customers.CustomerLastName
FROM Customers
JOIN Orders ON Customers.Customer_Id = Orders.Customer_Id
AND Orders.Amount=(
          SELECT min(Amount) FROM Orders
          WHERE Customers.Customer_Id = Orders.Customer_Id 
        )

Answer 3

尝试一下。

返回交易金额最低的客户的姓氏和名字

select CustomerFirstName,CustomerLastName
from Customer
where   Customer_Id in (
SELECT DISTINCT Customer_Id
from  Orders
where Amount=(select min(Amount) from orders))

根据2个表格中的最低顺序获取客户名称

3 个答案: