Sql server 确定SQL Server中的连续日期计数

我有一些数据如下所示：

id     date
--------------------------------
123    2013-04-08 00:00:00.000
123    2013-04-07 00:00:00.000
123    2013-04-06 00:00:00.000
123    2013-04-04 00:00:00.000
123    2013-04-03 00:00:00.000

---

我需要返回给定ID的最近连续日期条纹计数，在本例中，对于ID

123

，该计数为

3

。我不知道这是否可以在SQL中完成。有什么建议吗？

方法是将一系列数字相减，然后取差。这是一个日期序列的常数。以下是获取id的所有序列长度的示例：

select id, grp, count(*) as NumInSequence, min(date), max(date)
from (select t.*,
             (date - row_number() over (partition by id order by date)) as grp
      from data t
     ) t
group by id, grp

要获得最长的一个，我将再次使用

行编号（）

select t.*
from (select id, grp, count(*) as NumInSequence,
             min(date) as mindate, max(date) as maxdate,
             row_number() over (partition by id order by count(*) desc) as seqnum
      from (select t.*,
                   (date - row_number() over (partition by id order by date)) as grp
            from data t
           ) t
      group by id, grp
     ) t
where seqnum = 1