选择“ N”个连续的“ X”记录组

Question

我需要从这样的列表中过滤“ N”个连续的“ X”记录组：

1
4
5
6
9
12

在样本列表中，当X = 2时，连续的“ X”记录组为：

4,5
5,6

有没有一种方法可以使用SQL Server 2008的窗口函数来获得该结果？

Answer 1

如何？

DECLARE @x int = 2;

WITH 
  consecutive_groups (n, grp) AS (
    SELECT n, n - ROW_NUMBER() OVER (ORDER BY n)
    FROM NumbersTable
  ),
  groups_with_minmax (n, grp, nMin, nMax) AS (
    SELECT n, grp
      , MIN(n) OVER (PARTITION BY grp)
      , MAX(n) OVER (PARTITION BY grp)
    FROM consecutive_groups
  )
SELECT n AS SequenceStart, n+@x-1 AS SequenceEnd
FROM groups_with_minmax
WHERE n+@x-1 BETWEEN nMin AND nMax;

使用的所有窗口函数应在SQL Server 2008中可用。