Question

table master

如何根据1天的日期间隔对row_num进行排序？

使用netezza进行如下输出：

after sort and reset row num table master

Answer 1

如果仅依靠基于集合的逻辑和Windows函数（行号等），这是困难的，因为您需要不断查看下一行以确定日期是否为在当前的1天内。

直觉是您将需要游标或while循环逻辑。

一个“快速”解决方案是对数据运行预解析脚本，以得出“匹配组”值。

一旦有了匹配的组值，就可以轻松使用Windows函数。

类似的事情（最有可能采用其他/更好的方法得出匹配组）。

我还添加了RowId INT作为主键，以便您可以使用+或-逻辑（前进/后退）轻松地自我加入。

基本上，当下一个日期位于当前日期的0到1天之间时，循环遍历添加匹配组INT的数据。

DECLARE
    @TestData TABLE
    (
        [Id] UNIQUEIDENTIFIER,
        [Date] DATETIME,
        RowId INT IDENTITY (1, 1) PRIMARY KEY,
        MatchGroupKey INT
    );

INSERT INTO @TestData
(
    Id,
    [Date]
)
VALUES
(
    NEWID(), '20190504'
),
(
    NEWID(), '20190513'
),
(
    NEWID(), '20190515'
),
(
    NEWID(), '20190516'
),
(
    NEWID(), '20190517'
),
(
    NEWID(), '20190521'
),
(
    NEWID(), '20190522'
),
(
    NEWID(), '20190523'
),
(
    NEWID(), '20190524'
),
(
    NEWID(), '20190526'
),
(
    NEWID(), '20190527'
);

-- Derive a "match group" key

DECLARE
    @LoopCounter INT = 1,
    @TotalRows INT =
    (
        SELECT
            COUNT(*)
        FROM
            @TestData
    );

DECLARE
    @CurrentID UNIQUEIDENTIFIER,
    @CurrentDate DATETIME,
    @CurrentRowId INT,
    @NextID UNIQUEIDENTIFIER,
    @NextDate DATETIME,
    @NextRowId INT,
    @MatchGroupKey INT = 1;

WHILE (@LoopCounter <= @TotalRows)
BEGIN

    -- Get current row
    SELECT
        @CurrentID = Id,
        @CurrentDate = [Date],
        @CurrentRowId = RowId
    FROM
        @TestData
    WHERE
        RowId = @LoopCounter;

    --Get next row
    SELECT
        @NextID = Id,
        @NextDate = [Date],
        @NextRowId = RowId
    FROM
        @TestData
    WHERE
        RowId = @LoopCounter + 1;

    IF DATEDIFF(dd, @CurrentDate, @NextDate) BETWEEN 0 AND 1
    BEGIN

        --If next row is same or within 1 day then update current/previous with match group

        UPDATE
            t1
        SET
            t1.MatchGroupKey = @MatchGroupKey
        FROM
            @TestData t1
        WHERE
            t1.RowId IN (@LoopCounter, @LoopCounter + 1);

    END; ELSE BEGIN

        --If next row is not within the 1 day then update just the current row with match value and increment the match value for next iteration
        UPDATE
            t1
        SET
            t1.MatchGroupKey = @MatchGroupKey
        FROM
            @TestData t1
        WHERE
            t1.RowId IN (@LoopCounter);

        SET @MatchGroupKey += 1;

    END;

    SET @LoopCounter += 1;

END;

结果

3FEADF3A-8380-46C6-8280-314FD2F619FB    2019-05-04 00:00:00.000 1   1
C487A5B9-285C-4C4F-A2BD-D1AD6272BEC2    2019-05-13 00:00:00.000 2   2
273E41FD-B910-42AB-BF22-ECE9B13B2EDA    2019-05-15 00:00:00.000 3   3
4C5E8A74-8B2E-41D8-9F32-012EBB030631    2019-05-16 00:00:00.000 4   3
1794C36E-CAA1-430C-9BB2-CECC1A85BBCE    2019-05-17 00:00:00.000 5   3
853B8296-5040-44CF-8F1C-F3E9CF5ADC24    2019-05-21 00:00:00.000 6   4
7E7E4288-13CC-4060-BCFF-A75FB4554B1D    2019-05-22 00:00:00.000 7   4
745BEE56-C2CC-4FC8-939F-DB1F5C713015    2019-05-23 00:00:00.000 8   4
F25613A6-B7CF-4131-A697-CC3A974595FC    2019-05-24 00:00:00.000 9   4
F98A02AD-8570-4A7D-B752-A34648949498    2019-05-26 00:00:00.000 10  5
D582E2BB-7625-4E12-8A09-90D1C2E769EC    2019-05-27 00:00:00.000 11  5

所以现在您在最后一列中有一个匹配组值。

现在很容易获得结果：

SELECT
    Id,
    [Date],
    ROW_NUMBER() OVER (PARTITION BY MatchGroupKey ORDER BY Date) rn
FROM
    @TestData;

结果

5204D618-B0D9-4186-AD18-7A7C4D4220B2    2019-05-04 00:00:00.000 1
F263AAAD-1CC3-4BDE-8E16-4DE890D0012B    2019-05-13 00:00:00.000 1
8FAD9002-3951-4E63-B012-C3C9E87D7700    2019-05-15 00:00:00.000 1
26CB938B-638D-40F4-B18D-6225EBF6F739    2019-05-16 00:00:00.000 2
472646E4-FD36-43E0-B579-F542AFA7110B    2019-05-17 00:00:00.000 3
7EB4248D-B942-423B-A756-FF9438CD80DF    2019-05-21 00:00:00.000 1
103027EC-5D5E-4BD9-99A8-44274F0BE383    2019-05-22 00:00:00.000 2
79609995-D2CE-443E-AE17-DE3D9B4B6F40    2019-05-23 00:00:00.000 3
273ADCD6-0CC8-4DB9-9627-CC6FAA87D388    2019-05-24 00:00:00.000 4
3D6E53F0-976F-4FFC-936B-9503E28DE862    2019-05-26 00:00:00.000 1
573ED4AC-F370-48E5-BE79-65A847AD6CA4    2019-05-27 00:00:00.000 2

如何重设行号？

1 个答案:

结果

结果