根据两个值（时间，ID）向前填充

Question

我正在使用SQL Server 2014，我想根据两列填写：日期和ID。 如果ID改变，那么我需要停止前一个前转

这是我的数据集：

   Date         Id       Score
--------------------------------------------
   201508         1           24
   201509         1           NULL
   201510         1           NULL
   201511         1           25
   201512         1           NULL
   201601         1           30
   201602         1           NULL
   201508         2           NULL
   201509         2           NULL
   201508         3           10
   201509         3           NULL

所以我想得到以下内容：

   Date         Id       Score
--------------------------------------------
   201508         1           24
   201509         1           24
   201510         1           24
   201511         1           25
   201512         1           25
   201601         1           30
   201602         1           30
   201508         2           NULL
   201509         2           NULL
   201508         3           10
   201509         3           10

我试过这样的事但没有成功

SELECT
  a.*,
  COALESCE(a.Score, b.Score) AS FILLED_IN_VALUE
FROM 
  data a
  OUTER APPLY (
    SELECT TOP 1 x.Score
    FROM data x 
    WHERE 
      a.Score IS NULL 
      AND x.Score IS NOT NULL
      AND x.ID < a.ID
      AND x.Date < a.Date
    ORDER BY a.ID ASC, a.Date ASC
    ) b

Answer 1

使用运行总和将行分类到组中。然后获得每组的最高分数。

select date,id,max(score) over(partition by id,grp) as score
from (select date,id,score,
      sum(case when score is not null then 1 else 0 end) over(partition by id order by date) as grp
      from tbl
     ) t