Question

我在SQL中有一个摘录，我想按照下表所示的格式对所需输出列中的数据进行分组/排名。我的问题是如何实现这一目标。我已经尝试过Rank和Dense rank功能，但它没有给我想要的结果。

Cusomter_Id | Rno | Start_Dt | End_Dt | PM_Status | Desired_Output
-------------------------------------------------- -----------------------
1609 | 1 | 02/10/2014 | 08/10/2014 | VD | 1
-------------------------------------------------- -----------------------
1609 | 2 | 09/10/2014 | 02/11/2014 | CC | 2
-------------------------------------------------- -----------------------
1609 | 3 | 03/11/2014 | 04/11/2014 | CC | 2
-------------------------------------------------- -----------------------
1609 | 4 | 05/11/2014 | 27/01/2015 | FD | 3
-------------------------------------------------- -----------------------
1609 | 5 | 28/01/2015 | 02/02/2015 | CC | 4
-------------------------------------------------- -----------------------
1609 | 6 | 03/02/2015 | 09/02/2015 | CC | 4
-------------------------------------------------- -----------------------
1609 | 7 | 10/02/2015 | 31/12/9999 | CC | 4
-------------------------------------------------- -----------------------

我希望上述数据有意义，请告诉我。

非常感谢您查看我的查询。

Answer 1

您可以使用递归CTE查找分组并获得所需结果：

DECLARE @Data TABLE (
    Customer_Id INT,
    Rno INT,
    Start_Dt DATE,
    End_Dt DATE,
    PM_Status VARCHAR(5),
    Desired INT
)
INSERT @Data VALUES
    (1609, 1, '2/10/2014', '10/8/2014', 'VD', 1),
    (1609, 2, '10/9/2014', '11/2/2014', 'CC', 2),
    (1609, 3, '11/3/2014', '11/4/2014', 'CC', 2),
    (1609, 4, '11/5/2014', '1/27/2014', 'FD', 3),
    (1609, 5, '1/28/2015', '2/2/2015', 'CC', 4),
    (1609, 6, '2/3/2015', '2/9/2015', 'CC', 4),
    (1609, 7, '2/10/2015', NULL, 'CC', 4)

; WITH CTE AS (
    SELECT
        Customer_id,
        Rno,
        Start_Dt,
        End_Dt,
        PM_Status,
        Desired,
        1 AS Actual
    FROM @Data
    WHERE RNo = 1
    UNION ALL
    SELECT
        SRC.Customer_id,
        SRC.Rno,
        SRC.Start_Dt,
        SRC.End_Dt,
        SRC.PM_Status,
        SRC.Desired,
        CASE WHEN CTE.PM_Status <> SRC.PM_Status 
            THEN CTE.Actual + 1 ELSE CTE.Actual END
    FROM CTE
        INNER JOIN @Data SRC
            ON SRC.Customer_Id = CTE.Customer_Id
                AND SRC.Rno = CTE.Rno + 1
)
SELECT *
FROM CTE

输出：

Customer_id Rno         Start_Dt   End_Dt     PM_Status Desired     Actual
----------- ----------- ---------- ---------- --------- ----------- -----------
1609        1           2014-02-10 2014-10-08 VD        1           1
1609        2           2014-10-09 2014-11-02 CC        2           2
1609        3           2014-11-03 2014-11-04 CC        2           2
1609        4           2014-11-05 2014-01-27 FD        3           3
1609        5           2015-01-28 2015-02-02 CC        4           4
1609        6           2015-02-03 2015-02-09 CC        4           4
1609        7           2015-02-10 NULL       CC        4           4

sql server汇总或分组数据

1 个答案: