在单行中组合/合并多列唯一值

Posted 2023-02-16

【中文标题】在单行中组合/合并多列唯一值

【英文标题】：Combining/merging multiple columns unique values in a single row

【发布时间】：2018-10-08 16:01:22

【问题描述】：

尝试将多个列和行与 SSMS 中的单个查询组合在一起。这是我正在使用的更复杂表的更简单版本：

这是我当前的查询：

CREATE TABLE Table1
([C1] varchar(50), [C2] varchar(50), [C3] varchar(50))
;

INSERT INTO Table1
([C1], [C2], [C3])
VALUES
('F92', 'Game1', 'b100'),
('F92', 'Game1', 'b200'),
('F92', 'Game2', 'C200'),
('F92', 'Game2', 'D400')
;



SELECT
 C1,C2,
 STUFF(
     (SELECT ', ' + C3
      FROM Table1
      WHERE C1 = a.C1 AND C2 = a.C2
      FOR XML PATH (''))
      , 1, 1, '')  AS NamesList
FROM Table1 AS a
GROUP BY C1,C2

drop table table1

我打算得到如下结果：

C1   | Namelist
F92  | Game1 b100, b200 Game2 c200, d400

这在单个查询中可行吗？

【问题讨论】：

发布 ddl、示例数据和所需输出的工作真是太棒了。当您努力发布这么多信息时，它真的很容易提供帮助。

【参考方案1】：

扩展这个例子。这是新的查询：

            CREATE TABLE Table1
            ([C1] varchar(50), [C2] varchar(50), [C3] varchar(50),[C4] varchar(50),[C5] varchar(50) )
            ;

            INSERT INTO Table1
            ([C1], [C2], [C3], [C4], [C5])
            VALUES
            ('F92', 'XBOX','81-94','Game1', 'B350'),
            ('F92', 'XBOX','81-94','Game1', 'B150'),
            ('F92', 'XBOX','76-80','Game2', 'PB100'),
            ('F92', 'XBOX','76-80','Game2', 'PB200'),
            ('F92', 'XBOX','95-97','Game2', 'PB300')
            ;

            with FirstPass as
            (
                SELECT
                 C1, c2, 
                    c3 + ' ' + c4+ + STUFF(
                     (SELECT ', ' +''+ c5
                      FROM Table1
                      WHERE C1 = a.C1 AND C2 = a.C2  AND C3 = a.C3  AND C4 = a.C4  
                      FOR XML PATH (''))
                      , 1, 1, '')  AS NamesList
                , count(*) as GameCount
                FROM Table1 AS a
                GROUP BY C1,C2,c3, c4
            )

            select distinct C1,C2
                , NameList = stuff((select ' ' + fp2.NamesList
                    from FirstPass fp2
                    where fp.C1 = fp2.C1
                    group by fp2.GameCount, fp2.NamesList
                    order by fp2.GameCount
                    FOR XML PATH('')), 1, 1, '')
                    into table2
            from FirstPass fp

            -- concatenate and insert into existing table

            insert into table2 (C1, conc)
            select C1, C2 + ' ' + NameList
            from FirstPass fp

            SELECT *  FROM table2


            drop table table1
            drop table table2

想要的结果：

C1  |conc
F92 |XBOX 95-97 GAME2 PB300 76-80 GAME2 PB100, PB200 81-94 GAME1 B350, B150

并将此结果插入现有表“table2”

在这里连接最好的解决方案是否达到了预期的结果？查询的这一部分让我失望：

-- concatenate and insert into existing table

            insert into table2 (C1, conc)
            select C1, C2 + ' ' + NameList
            from FirstPass fp

【参考方案2】：

当然可以。您可以使用 cte 来获取您已经获得的分隔列表。然后获取结果并将其转换为另一个分隔列表。但是您可能需要一些东西作为组之间的分隔符，而不是空格。

with FirstPass as
(
    SELECT
     C1,
     C2 + ' ' + STUFF(
         (SELECT ', ' + C3
          FROM Table1
          WHERE C1 = a.C1 AND C2 = a.C2
          FOR XML PATH (''))
          , 1, 1, '')  AS NamesList
    FROM Table1 AS a
    GROUP BY C1,C2
)

select C1
    , NameList = stuff((select ' ' + fp2.NamesList
        from FirstPass fp2
        where fp.C1 = fp2.C1
        FOR XML PATH('')), 1, 1, '')
from FirstPass fp
group by fp.C1

返回：

F92 |游戏1 b100、b200 游戏2 C200、D400

--编辑--

根据需要按计数对 C2 进行排序的新要求，您可以简单地添加一点聚合。这与原来的变化不大。

with FirstPass as
(
    SELECT
     C1,
     C2 + ' ' + STUFF(
         (SELECT ', ' + C3
          FROM Table1
          WHERE C1 = a.C1 AND C2 = a.C2
          FOR XML PATH (''))
          , 1, 1, '')  AS NamesList
    , count(*) as GameCount
    FROM Table1 AS a
    GROUP BY C1,C2
)

select distinct C1
    , NameList = stuff((select ' ' + fp2.NamesList
        from FirstPass fp2
        where fp.C1 = fp2.C1
        group by fp2.GameCount, fp2.NamesList
        order by fp2.GameCount desc
        FOR XML PATH('')), 1, 1, '')
from FirstPass fp

【讨论】：

感谢就像一个魅力。所以这是我陷入困境的另一点（不知道我是否应该创建一个新票）。

如果可行，您应该考虑将其标记为答案。

【参考方案3】：

说现在的值是

 VALUES
('F92', 'Game1', 'b100'),
('F92', 'Game1', 'b200'),
('F92', 'Game2', 'C200'),
('F92', 'Game2', 'D400'),
('F92', 'Game2', 'D500')
;

所以现在 Game2 出现了 3 次。使用 Sean Lange 的代码结果按升序排列，因此 Game1 出现在 Game2 之前。有没有办法根据 c2 列的计数（降序）显示结果，所以预期的结果是

F92 | Game2 C200, D400, D500 Game1 b100, b200