Question

我在SQL服务器中创建了3个名为t_user_master，t_product_master和t_transaction的表.t_user_master通过列Users_id与t_transaction链接，而__product_master与t_transaction链接虽然列Products_id.Now我必须生成并输出包含的users_name（来自t_user_master），Product_name（来自t_product_master）与之链接，以便查看哪个用户订购了哪个产品。这是我的代码片段 -

 SELECT um.Users_Name,
       pm.Product_Name,
       (SELECT SUM(Transaction_Amount)
        FROM   t_transaction
        WHERE  Transaction_Type = 'Order'
        GROUP  BY Users_Id,
                  Product_Id) AS Ordered_quantity,
       (SELECT SUM(Transaction_Amount)
        FROM   t_transaction
        WHERE  Transaction_Type = 'Payment'
        GROUP  BY Users_ID,
                  Product_Id) AS Amount_Paid,
       (SELECT MAX(Transaction_Date)
        FROM   t_transaction
        GROUP  BY Users_Id,
                  Product_Id) AS Last_Transaction_Date,
       (SELECT ( ( SUM(Transaction_Amount) * pm.Cost_per_Item ) - SUM(Transaction_Amount) ) )AS Balance
        FROM   t_user_master um
               JOIN t_transaction tr
                 ON um.Users_ID = tr.Users_ID
               JOIN t_product_master pm
                 ON tr.Product_ID = pm.Product_ID
    GROUP BY um.Users_Name,pm.Product_Name

我已经记下了与语法相关的所有错误，但现在我面临另一个问题。执行后我收到此消息-Column't_product_master.Cost_Per_Item'在选择列表中无效，因为它不包含在聚合中函数或GROUP BY子句。我哪里错了？

Answer 1

你错过了第10行末尾的“）”和Last_Transaction_Date之后的“，”。试试这个：

SELECT    um.Users_Name,pm.Product_Name,
(SELECT   SUM(Transaction_Amount)
 FROM     t_transaction 
 WHERE    Transaction_Type='Order' 
 GROUP BY Users_Id,Product_Id
) AS Ordered_quantity,
(SELECT   SUM(Transaction_Amount)
 FROM     t_transaction 
 WHERE    Transaction_Type='Payment'
 GROUP BY Users_ID,Product_Id
) AS Amount_Paid,
(SELECT   MAX(Transaction_Date)
 FROM     t_transaction 
 GROUP BY Users_Id,Product_Id
) AS Last_Transaction_Date,
(SELECT   ( ( SUM(Transaction_Amount)*pm.Cost_per_Item ) - SUM(Transaction_Amount) )
) AS Balance
FROM      t_user_master um 
JOIN      t_transaction tr ON um.Users_ID=tr.Users_ID
JOIN      t_product_master pm ON tr.Product_ID = pm.Product_ID

GROUP BY um.Users_Name,pm.Product_Name

Answer 2

至少你错过了这一行末尾的“，”：

GROUP BY Users_Id,Product_Id) AS Last_Transaction_Date

Answer 3

你在LastTransactionDate之后错过了一个逗号，而SELECT的最后一列看起来格格不入，即

(SELECT ((SUM(Transaction_Amount)*pm.Cost_per_Item)-SUM(Transaction_Amount)) AS Balance

Answer 4

您的查询实际上有三个问题：

Last_Transaction_Date之后缺少逗号。
选择余额时结束括号。
计算余额时，您使用了pm.Cost_per_Item。完成GROUP BY之后，将对结果分组行计算所有select语句列。我使用了sum，但你可以根据需要使用任何其他聚合函数。

正确的查询是：

SELECT um.Users_Name,
    pm.Product_Name,
    (SELECT SUM(Transaction_Amount) FROM t_transaction 
    WHERE Transaction_Type='Order' 
    GROUP BY Users_Id,Product_Id) AS Ordered_quantity,
    (SELECT SUM(Transaction_Amount) FROM t_transaction 
    WHERE Transaction_Type='Payment'
    GROUP BY Users_ID,Product_Id )AS Amount_Paid,
    (SELECT MAX(Transaction_Date) FROM t_transaction 
      GROUP BY Users_Id,Product_Id) AS Last_Transaction_Date, -- error 1
     (SELECT ((SUM(Transaction_Amount)* sum(pm.Cost_per_Item))-SUM(Transaction_Amount))) AS 
      Balance -- error 2 and error 3
FROM t_user_master um 
JOIN t_transaction tr ON um.Users_ID=tr.Users_ID
JOIN t_product_master pm ON tr.Product_ID = pm.Product_ID
GROUP BY um.Users_Name,pm.Product_Name ;

希望这有帮助!!!

为什么它给出了错误的语法？

4 个答案: