当日期字段更改月

Question

我目前正在执行以下查询：

Select *, Balance = SUM(DailyReAdmits) 
OVER (ORDER BY Date_Total ROWS UNBOUNDED PRECEDING) 
From #AllReadmits

返回以下结果：

Date_Total    DailyReAdmits    Balance
2015-08-25                4          4
2015-08-26                8         12
2015-08-27                9         21
2015-08-28                3         24
2015-08-29                1         25
2015-08-30                4         29
2015-08-31                3         32
2015-09-01                5         37

但是，当新月开始时，我希望余额重新开始，看起来像这样：

Date_Total    DailyReAdmits    Balance
2015-08-25                4          4
2015-08-26                8         12
2015-08-27                9         21
2015-08-28                3         24
2015-08-29                1         25
2015-08-30                4         29
2015-08-31                3         32
2015-09-01                5          5

我怎样才能做到这一点？

Answer 1

我认为你想按月分区，所以试试这个：

SELECT *, Balance = SUM(DailyReAdmits) 
OVER (PARTITION BY DATEPART(MM,Date_Total) ORDER BY Date_Total ROWS UNBOUNDED PRECEDING) 
FROM #AllReadmits