Question

我正在尝试开发一个T-SQL例程（SQL Server 2014），这将允许我查找组内所有记录组合。

鉴于以下数据：

ID_COMBINATION | ID_POSITION | MULTIPLY_FACTOR
-----------------------------------------------    
       1       |        1    |        1
       1       |        1    |        2
       1       |        1    |        3
       1       |        2    |        1
       1       |        2    |        2
       1       |        2    |        3

我想计算给定ID_COMBINATION的全套ID_POSITIONS的MULTIPLY_FACTOR组合

结果应为：

1 | 1 | 1
1 | 2 | 1
1 | 1 | 1
1 | 2 | 2
1 | 1 | 1
1 | 2 | 3
...
1 | 1 | 3
1 | 2 | 3

目前我更喜欢关闭例程定义（在运行时使用动态SQL生成多重交叉连接代码，具体取决于组中唯一ID_POSITIONS的数量）

非常感谢你的帮助！

修改

以下TSQL代码计算给定ID_COMBINATION 1的唯一ID_POSITION的组合：

declare @Samples as Table ( Id_Combination Int, Id_Position Int, Multiply_Factor Int );
INSERT INTO @Samples (Id_Combination, Id_Position, Multiply_Factor)
    VALUES (1, 1, 1), (1, 1, 2), (1, 1, 3)
    , (1, 2, 1), (1, 2, 2), (1, 2, 3)

SELECT
    S1.Id_Combination
    ,S1.Id_Position AS s1_idpos
    ,S1.Multiply_Factor AS s1_mufac
    ,S2.Id_Position AS s2_idpos
    ,S2.Multiply_Factor AS s2_mufac
FROM @Samples AS S1
INNER JOIN @Samples AS S2
    ON s1.Id_Combination = s2.Id_Combination
    AND s1.Id_Position < s2.Id_Position

但是，如果我添加一个具有相应MULTPLY_FACTOR值的新ID_POSITION键，我将不得不修改连接条件并选择语句以涵盖新场景，例如：

declare @Samples as Table ( Id_Combination Int, Id_Position Int, Multiply_Factor Int );
INSERT INTO @Samples (Id_Combination, Id_Position, Multiply_Factor)
    VALUES (1, 1, 1), (1, 1, 2), (1, 1, 3)
    ,(1, 2, 1), (1, 2, 2), (1, 2, 3),
    ,(1, 3, 1), (1, 3, 2), (1, 3, 3);

    SELECT
        S1.Id_Combination
        ,S1.Id_Position AS s1_idpos
        ,S1.Multiply_Factor AS s1_mufac
        ,S2.Id_Position AS s2_idpos
        ,S2.Multiply_Factor AS s2_mufac
        ,S3.Id_Position AS s3_idpos
        ,S3.Multiply_Factor AS s3_mufac
    FROM @Samples AS S1
    INNER JOIN @Samples AS S2
        ON s1.Id_Combination = s2.Id_Combination
        AND s1.Id_Position < s2.Id_Position
    INNER JOIN @Samples AS S3
        ON s2.Id_Combination = s3.Id_Combination
        AND s2.Id_Position < s3.Id_Position

回到我的问题一般想法：如何写＆＃34;泛型＆＃34;这里的TSQL代码将覆盖ID_POSITION域中所有可能的未来值，并垂直显示值，而不是在SELECT子句中添加新字段。当然，必须引入一些SUB_COMBINATION键，以使这些组合在父ID_COMBINATION中彼此不同...

Answer 1

由于我无法弄清楚你的评论：“ID_POSITION的大小”，我只想问为什么这不容易：

-- Sample data.
declare @Samples as Table ( Id_Combination Int, Id_Position Int, Multiply_Factor Int );
insert into @Samples ( Id_Combination, Id_Position, Multiply_Factor ) values
  ( 1, 1, 1 ), ( 1, 1, 2 ), ( 1, 1, 3 ), -- ( 1, 1, 4 ), -- Try me.
  ( 1, 2, 1 ), ( 1, 2, 2 ), ( 1, 2, 3 );
select * from @Samples;

-- Generate all possible combinations of all values.
select distinct S1.Id_Combination, S2.Id_Position, S3.Multiply_Factor
  from @Samples as S1 cross join @Samples as S2 cross join @Samples as S3
  order by Id_Combination, Id_Position, Multiply_Factor;

请注意，如果您取消注释额外的示例数据行，您将获得两个更多结果行。

TSQL：查找组内没有交叉连接的行组合

1 个答案: