GROUP BY在SQL连续行(GROUP BY for continuous rows in SQ

如下表：

ID   State  Date
12   1      2009-07-16 10:00
45   2      2009-07-16 13:00
67   2      2009-07-16 14:40
77   1      2009-07-16 15:00
89   1      2009-07-16 15:30
99   1      2009-07-16 16:00

题：
我怎么能集团由场“国家”，同时仍然保持状态的变化之间的边界？

SELECT MIN(ID) AS ID, State, MIN(Date) AS Date, COUNT(ID) AS Count
FROM table GROUP BY State

结果如下：

ID   State  Date              Count
12   1      2009-07-16 10:00  4
45   2      2009-07-16 13:00  2

但预计：

ID   State  Date              Count
12   1      2009-07-16 10:00  1
45   2      2009-07-16 13:00  2
77   1      2009-07-16 15:00  3

这是可能的SQL？我没有找到一个解决方案至今...

Answer 1:

SELECT  MIN(id) AS id, MIN(ts) AS ts, MIN(state) AS state, COUNT(*) cnt
FROM    (
        SELECT  @r := @r + (@state != state) AS gn,
                @state := state AS sn,
                s.*
        FROM    (
                SELECT  @r := 0,
                        @state := 0
                ) vars,
                t_state s
        ORDER BY
                ts
        ) q
GROUP BY
        gn

测试表创建脚本：

CREATE TABLE t_state (id INT NOT NULL PRIMARY KEY, state INT NOT NULL, ts DATETIME NOT NULL);

INSERT
INTO  t_state
VALUES
(12,   1,      '2009-07-16 10:00'),
(45,   2,      '2009-07-16 13:00'),
(67,   2,      '2009-07-16 14:40'),
(77,   1,      '2009-07-16 15:00'),
(89,   1,      '2009-07-16 15:30'),
(99,   1,      '2009-07-16 16:00');

Answer 2:

这是如何与热膨胀系数做MSSQL服务器上

-- DROP TABLE MyLog
CREATE TABLE MyLog(
        ID          INT PRIMARY KEY
        , State     INT
        , Date      DATETIME
        )
INSERT MyLog
SELECT 12, 1, '2009-07-16 10:00' UNION ALL
SELECT 45, 2, '2009-07-16 13:00' UNION ALL
SELECT 67, 2, '2009-07-16 14:40' UNION ALL
SELECT 77, 1, '2009-07-16 15:00' UNION ALL
SELECT 89, 1, '2009-07-16 15:30' UNION ALL
SELECT 99, 1, '2009-07-16 16:00'

;WITH   CTE
AS      (
        SELECT  ROW_NUMBER() OVER(ORDER BY ID) AS RowNo
                , *
        FROM    MyLog
        )
, MyLogGroup
AS      (
        SELECT  l.*
                , ( SELECT  MAX(ID)
                    FROM    CTE c
                    WHERE   NOT EXISTS (SELECT * FROM CTE
                                        WHERE RowNo = c.RowNo-1 AND State = c.State)
                            AND c.ID <= l.ID) AS GroupID
        FROM    MyLog l
        )
SELECT  *
FROM    MyLogGroup