如何获取此查询中的实际运行余额

Question

继我从昨天最初提出的问题(here)后，我能够构建下面的SQL查询，该查询生成了运行的发票和付款清单。

SELECT 
    'Invoice' AS TransactionType, 
    i.InvoiceNumber AS Description, 
    i.InvoiceDate AS TransactionDate, 
    CAST(ROUND(i.OutstandingBalance, 2) AS DECIMAL(12, 2)) AS TransactionAmount 
FROM 
    Invoices i 
WHERE 
    i.CustomerId = 12 
    AND i.InvoiceDate BETWEEN '20150601' AND '20160229' 
    AND i.OutstandingBalance > 0.02 

UNION 

SELECT 
    'Payment' AS TransactionType, 
    ip.InvoicePaymentId AS Description, 
    ip.InvoicePaymentDate AS TransactionDate, 
    - ip.Amount AS TransactionAmount 
FROM 
    InvoicePayments ip 
WHERE 
    ip.CustomerId = 12 
    AND ip.InvoicePaymentDate BETWEEN '20150601' AND '20160229' 
ORDER BY 
    TransactionDate 

我现在想要做的是产生一个额外的列，它实际上是帐户上的运行余额。我想，如果我开始使用一个变量，那么应该可以添加（或从中减去给我的东西）。为此，我尝试了以下内容;

DECLARE @OutstandingBalance MONEY = 0 

SELECT 
    'Invoice' AS TransactionType, i.InvoiceNumber AS Description, 
    i.InvoiceDate AS TransactionDate, 
    CAST(ROUND(i.OutstandingBalance, 2) AS DECIMAL(12, 2)) AS TransactionAmount, 
    @OutstandingBalance + CAST(ROUND(i.OutstandingBalance, 2) AS DECIMAL(12, 2)) AS Balance 
FROM 
    Invoices i 
WHERE 
    i.CustomerId = 12 
    AND i.InvoiceDate BETWEEN '20150601' AND '20160229' 
    AND i.OutstandingBalance > 0.02 

哪产生了下面的结果。

但是试图通过使它@OutstandingBalance + =像这样修改的查询;

DECLARE @OutstandingBalance MONEY = 0 

SELECT 
    'Invoice' AS TransactionType, i.InvoiceNumber AS Description, 
    i.InvoiceDate AS TransactionDate, 
    CAST(ROUND(i.OutstandingBalance, 2) AS DECIMAL(12, 2)) AS TransactionAmount, 
    @OutstandingBalance += CAST(ROUND(i.OutstandingBalance, 2)AS DECIMAL(12,2)) AS Balance 
FROM 
    Invoices i 
WHERE 
    i.CustomerId = 12 
    AND i.InvoiceDate BETWEEN '20150601' AND '20160229' 
    AND i.OutstandingBalance > 0.02 

抛出一个错误告诉我，语法附近关键字AS（这我相信所指的平衡不正确。我怀疑，我应该是“设置”的@OutstandingBalance价值，但加入中的一组语句选择也会引发错误。

是否有可能在这种查询的创建运行平衡，如果是一个人如何适应设置@OutstandingBalance实现呢？

针对低于这个答案是结果集我得到：

编辑 修订查询以适应发票和付款：

SELECT 'Invoice' AS TransactionType, 
     i.InvoiceNumber AS Description, 
     i.InvoiceDate AS TransactionDate, 
     CAST(ROUND(i.OutstandingBalance,2)AS DECIMAL(12,2)) AS TransactionAmount , 
     SUM(CAST(ROUND(i.OutstandingBalance,2)AS DECIMAL(12,2))) OVER(ORDER BY i.InvoiceDate, i.InvoiceNumber) AS Balance 
FROM Invoices i 
WHERE i.CustomerId = 12 
AND i.InvoiceDate BETWEEN '20150601' AND '20160229' 
AND i.OutstandingBalance > 0.02 

UNION 

    SELECT 
    'Payment' AS TransactionType, 
    ip.InvoicePaymentId AS Description, 
    ip.InvoicePaymentDate AS TransactionDate, 
    - ip.Amount AS TransactionAmount, 
    SUM(CAST(ROUND(-ip.Amount,2) AS DECIMAL(12,2))) OVER(ORDER BY ip.InvoicePaymentDate,ip.InvoicePaymentId) AS Balance 

    FROM InvoicePayments ip 
    WHERE ip.CustomerId = 12 
    AND ip.InvoicePaymentDate BETWEEN '20150601' AND '20160229' 



ORDER BY TransactionDate, Description 

将会产生如下：

Answer 1

您可以使用SUM像这样的OVER条款：

SELECT 'Invoice' AS TransactionType, 
     i.InvoiceNumber AS Description, 
     i.InvoiceDate AS TransactionDate, 
     CAST(ROUND(i.OutstandingBalance,2)AS DECIMAL(12,2)) AS TransactionAmount , 
     SUM(CAST(ROUND(i.OutstandingBalance,2)AS DECIMAL(12,2))) OVER(ORDER BY i.InvoiceDate, i.InvoiceNumber) AS Balance 
FROM Invoices i 
WHERE i.CustomerId = 12 
AND i.InvoiceDate BETWEEN '20150601' AND '20160229' 
AND i.OutstandingBalance > 0.02 
ORDER BY TransactionDate, Description 

你也可以使用一个CTE来保存一个投：

;WITH cte AS 
(
SELECT 'Invoice' AS TransactionType, 
     i.InvoiceNumber AS Description, 
     i.InvoiceDate AS TransactionDate, 
     CAST(ROUND(i.OutstandingBalance,2)AS DECIMAL(12,2)) AS TransactionAmount 
FROM Invoices i 
WHERE i.CustomerId = 12 
AND i.InvoiceDate BETWEEN '20150601' AND '20160229' 
AND i.OutstandingBalance > 0.02 
) 

SELECT TransactionType, 
     Description, 
     TransactionDate, 
     TransactionAmount, 
     SUM(TransactionAmount) OVER(ORDER BY TransactionDate, Description) AS Balance 
FROM cte 
ORDER BY TransactionDate, Description