Question

我有两张桌子发票和付款。发票有付款。我想写一个查询，显示未付发票和发票的剩余金额，这是通过汇总发票的付款并从发票金额中减去它来计算的。我尝试了这个查询，但它不起作用。请问我该怎么做。

SELECT Invoice.[Invoice Date], Invoice.Item, Invoice.Quantity, 
    Invoice.[Unit Price], 
    Invoice.[Payment Status], Invoice.[LongDate], 
    Invoice.Quantity*Invoice.[Unit Price] - Sum(Q.Amount) AS Remaining
FROM  
    (SELECT Invoice.[Invoice Id], [Payment ID]
       FROM Invoice 
       INNER JOIN Payment ON Invoice.[Invoice Id] = Payment.[Invoice Id]) AS Q
    INNER JOIN Invoice ON Q.[Invoice Id] = Invoice.[Invoice Id]
GROUP BY Invoice.[Invoice Id];

Answer 1

试试这个：

SELECT
    Invoice.[Invoice Id],
    Invoice.Quantity * Invoice.[Unit Price] - COALESCE(Amount, 0) AS Remaining
FROM Invoice
LEFT JOIN (
    SELECT [Invoice Id], SUM(Amount) AS Amount
    FROM Payment
    GROUP BY [Invoice Id]
) T1
ON Invoice.[Invoice Id] = T1.[Invoice Id]

当然你也需要将其他列添加到select中，但我不认为它们与这个问题有关，所以为了清楚起见我省略了它们。

以下是我用来测试的一些测试数据：

CREATE TABLE Invoice ([Invoice Id] INT NOT NULL, Quantity INT NOT NULL, [Unit Price] INT NOT NULL);
INSERT INTO Invoice ([Invoice Id], Quantity, [Unit Price]) VALUES
(1, 10, 5),
(2, 20, 10),
(3, 1, 1);

CREATE TABLE Payment ([Invoice Id] INT NOT NULL, Amount INT NOT NULL);
INSERT INTO Payment ([Invoice Id], Amount) VALUES
(1, 10),
(2, 100),
(2, 15);

这个数据的结果是：

Id  Remaining
1   40
2   85
3   1

Answer 2

SELECT Invoice.[Invoice ID], 
    Sum(Invoice.Quantity * Invoice.[Unit Price]) 
    - COALESCE(Sum(Payment.Amount), 0) AS Remaining
FROM
    Invoice LEFT JOIN Payment ON Invoice.[Invoice ID] = Payment.[Invoice ID]
GROUP BY Invoice.[Invoice ID]

编辑：我假设，结果中不需要与项目相关的信息使用LEFT JOIN时假设发票可能没有付款记录。

带和的Sql子查询

2 个答案: