（Ms Access）Row_Number（）Over分区

Question

如何使用MS ACCESS上的分区转换row_number（）函数？ 我想实现的是：

从这个表：

ID | EntryDate 
10 | 2016-10-10 
10 | 2016-12-10 
10 | 2016-12-31 
10 | 2017-01-31 
10 | 2017-03-31 
11 | 2015-01-31 
11 | 2017-01-31 

此输出，只显示前3最新每个ID：

ID | EntryDate 
10 | 2016-12-31 
10 | 2017-01-31 
10 | 2017-03-31 
11 | 2015-01-31 
11 | 2017-01-31 

在SQL Server中，我可以使用以下代码实现此目的：

select T.[ID], 
    T.[AptEndDate], 
from (
select T.[ID], 
     T.[AptEndDate], 
     row_number() over(partition by T.[ID] order by T.[AptEndDate] desc) as rn 
from Table1 as T 
) as T 
where T.rn <= 3; 

Answer 1

任何东西使用OVER子句称为窗口函数。不幸的是，MS Access没有在这种情况下，开窗Functions.The最简单的解决方案的支持可能是回VBA代码:(

Answer 2

考虑计数相关子查询可以在任何RDBMS工作。

select T.[ID], T.[EntryDate] 
from 
(select sub.[ID], 
     sub.[EntryDate], 
     (select count(*) from Table1 c 
      where c.ID = sub.ID 
      and c.[EntryDate] >= sub.[EntryDate]) as rn 
from Table1 as sub 
) as T 
where T.rn <= 3; 

Answer 3

这可能是更简单，更快地使用前n个 - 你提到自己：

Select T.[ID], T.[EntryDate] 
From Table1 As T 
Where T.[EntryDate] In 
    (Select Top 3 S.[EntryDate] 
    From Table1 As S 
    Where S.[ID] = T.[ID] 
    Order By S.[EntryDate] Desc) 
Order By T.[ID] Asc, T.[EntryDate] Asc