SQL查询选择序列号

Question

SQL查询选择序列号

在SQL Server中，我想根据序列号选择行。 例如我有如下数据：

ID RowNos
A  1
B  2
X  NULL
C  4
D  5
Y  NULL
E  7
F  8
G  9
H  11
I  13

查询应返回

ID NextID 
A  B      -- Since RowNos 1,2 is in sequence
C  D      -- Since RowNos 4,5 is in sequence
E  G      -- Since RowNos 7,8,9 is in sequence

我不知道要启动此查询。 否则，我也会发布我的试用版。

Answer 1

DECLARE @t TABLE (ID CHAR(1), RowNos INT)
INSERT INTO @t
VALUES
    ('A', 1), ('B', 2), ('X', NULL),
    ('C', 4), ('D', 5), ('Y', NULL),
    ('E', 7), ('F', 8), ('G', 9),
    ('H', 11), ('I', 13)

SELECT MIN(ID), MAX(ID)
FROM (
    SELECT *, rn = ROW_NUMBER() OVER (ORDER BY RowNos)
    FROM @t
) t
WHERE RowNos IS NOT NULL
GROUP BY RowNos - rn
HAVING MIN(ID) != MAX(ID)

输出：

---- ----
A    B
C    D
E    G

Answer 2

选择它们的顺序应该类似于：

SELECT * FROM table_name WHERE RowNos IS NOT NULL ORDER BY RowNos ASC;