使用 SQL 计算任何给定月份的 YTD 和先前 YTD

Question

我正在尝试构建一个图表，显示我有数据的任何给定月份的当前 YTD 和之前 YTD 的收入，通过 SQL 生成，可以随时从视图中检索到报告中。

表格看起来像这样

USER1 | MONTH | YEAR | REVENUE | YTD REVENUE | PRIOR YTD REVENUE |
------------------------------------------------------------------
Dan   | Feb   | 2016 |  $75    |   $75       |                   
Bob   | Feb   | 2016 |         |             |                   
Chris | Feb   | 2016 |  $220   |   $220      |     
Dan   | Jan   | 2017 |  $100   |   $100      |     
Bob   | Jan   | 2017 |  $150   |   $150      |     
Chris | Jan   | 2017 |  $200   |   $200      |     
Dan   | Feb   | 2017 |  $100   |   $200      |     $75
Bob   | Feb   | 2017 |  $100   |   $250      |     
Chris | Feb   | 2017 |  $125   |   $225      |     $220

作为构建所述视图的一部分，如何按月通过 sql 计算当前 YTD 和之前的 YTD？我目前没有按照上面的示例按月/年计算 YTD，因此在计算 PYTD 的同时还需要将其包含在语句中。

目前的SQL查询是

Select USER1, MONTH(Date), YEAR(Date), REVENUE from SOURCE 

Answer 1

您将使用窗口函数。这将假设“月”实际上是一个月数列。这比仅仅一个月更有意义：

select t.*,
       lag(ytd) over (partition by user1, month order by year) as prev_ytd
from (select t.*,
             sum(revenue) over (partition by user1, year order by month) as ytd
      from t
     ) t;

这假设所有用户都有相关月份的数据。

编辑：

如果您缺少行：

with tc as (
      select t.*,
             sum(revenue) over (partition by user1, year order by month) as ytd
      from t
     )
select tc.*, tcprev.ytd
from tc outer apply
     (select top (1) tcprev.ytd
      from tc tcprev
      where tcprev.user1 = tc.user1 and
            tcprev.year = tc.year and
            tcprev.month <= tc.month
      order by tcprev desc
     ) tcprev;