选择打开和关闭平衡从SQL Server表

Question

我需要这些表

TransDate Credit Debit Datasource 
------------------------------------------ 
2014-01-01 5000  NULL  3 
2014-01-07 NULL  2000  3 
2014-01-11 5000  NULL  3 
2014-02-03 5000  NULL  3 
2014-02-06 NULL  5000  4 
2014-02-11 5000  NULL  3 
2014-02-21 NULL  5000  4 
2014-02-28 5000  NULL  3 
2014-03-01 5000  NULL  3 

选择从数据库打开和关闭的平衡，但它给了我这个，please see here

我究竟做错了什么？

我期望太高看

TransDate Credit Debit  Balance 
------------------------------------------ 
2014-01-11 NULL  NULL  8000  <- opening balance  
2014-02-03 5000  NULL  
2014-02-06 NULL  5000  
2014-02-11 5000  NULL  
2014-02-21 NULL  5000  
2014-02-28 5000  NULL  13000  <- closing balance 

我的查询语句

Select 
    MAX(TransDate) TransDate, 0 Credit, 0 Debit, 
    SUM(ISNULL([Credit], 0) - ISNULL([Debit], 0)) AS Balance 
From 
    Transactions 
WHERE 
    DataSource = 4 OR DataSource = 3 
    AND TransDate < '2014/02/01' 

UNION 

Select 
    TransDate, Credit, Debit, 0 
From 
    Transactions 
WHERE 
    DataSource = 4 OR DataSource = 3 
    AND TransDate >= '2014/02/01' AND TransDate <= '2014/02/28' 

UNION 

Select 
    MIN(TransDate) TransDate, 0 Credit, 0 Debit, 
    SUM(ISNULL([Credit], 0) - ISNULL([Debit], 0)) AS Balance 
From 
    Transactions 
WHERE 
    DataSource = 4 OR DataSource = 3 
    AND TransDate >= '2014/02/01' AND TransDate <= '2014/02/28' 

Answer 1

在SQL Server 2012+，你可以使用累计总和：

select sum(coalesce(credit, 0) - coalesce(debit, 0)) over (order by transdate) as balance 
from table; 

你能拿第一，最后的余额使用多种方法，例如：

with b as (
     select t.* sum(coalesce(credit, 0) - coalesce(debit, 0)) over (order by transdate) as balance 
     from table t 
    ) 
select * 
from ((select top 1 b.* 
     from b 
     order by transdate 
    ) union all 
     (select top 1 b.* 
     from b 
     order by transdate desc 
    ) 
    ) b 

您也可以获得任何中间日期的余额。