sql-server - 如何删除select query over子句中的重复记录

Question

我在 SQL SERVER 中有如下的事务表。

 UserID       TranDate     Amount
    1   |   2015-04-01   |  0
    1   |   2015-05-02   |  5000
    1   |   2015-09-07   |  1000
    1   |   2015-10-01   |  -4000
    1   |   2015-10-02   |  -700
    1   |   2015-10-03   |  252
    1   |   2015-10-03   |  260
    1   |   2015-10-04   |  1545
    1   |   2015-10-05   |  1445
    1   |   2015-10-06   |  -2000

我想查询此表以获取任何特定日期的可用余额。所以我为此使用了窗口函数。

SELECT TransactionDate, 
    SUM(Amount) OVER (PARTITION BY UserId ORDER BY TransactionDate ROWS 
BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) FROM Transactions

但是由于事务表有日期 2015-10-03 的重复条目，它重复日期 2015-10-03 的数据。每当有相同的日期时，我都期待该日期的最后一条记录以及可用余额的总和。

当前输出

TransactionDate     AvailableBalance
   2015-04-01      |       0
   2015-05-02      |       5000
   2015-09-07      |       6000
   2015-10-01      |       2000
   2015-10-02      |       1300
   2015-10-03      |       1552
   2015-10-03      |       1804
   2015-10-04      |       3349
   2015-10-05      |       4794
   2015-10-06      |       2794

预期:我想从上面的结果集中删除下面的记录。

   2015-10-03      |       1552

HERE是我的 sql fiddle

Answer 1

您可以在窗口函数之前SUM，例如:

SqlFiddleDemo

WITH cte AS
(
  SELECT TransactionDate, UserId, SUM(Amount) AS Amount
  FROM Transactions
  GROUP BY TransactionDate, UserId
)
SELECT TransactionDate,  
        SUM(Amount) OVER (PARTITION BY UserId ORDER BY TransactionDate ROWS 
    BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) AS AvailableBalance 
FROM cte