SQL Server - 将行加入逗号分隔列表

问题描述

假设我有一个看起来像这样的临时表:

Let's suppose I have a temporary table which looks like this:

+----+------+
| Id | Value|
+----+------+    
| 1  |   1  |
| 1  |   2  |
| 1  |   3  |
| 2  |   1  |
| 2  |   2  |
+----+------+

我希望我的桌子是这样的:

And I want my table to be like this:

    +----+----------+
    | Id | ValueList|
    +----+----------+    
    | 1  |   1,2,3  |
    | 2  |   1,2    | 
    +----+----------+

所以基本上我需要将我的值分组为逗号分隔的列表.我已经尝试了以下方法:

So basically I need to group my values as a comma separated list. I already tried the following:

SELECT Id, STUFF((SELECT ',' + CAST(VALUE AS varchar) FROM @MyTable FOR XML PATH('')), 1 ,1, '') AS ValueList
FROM @MyTable
GROUP BY Id

但我得到类似的信息:

        +----+---------------------+
        | Id |      ValueList      |
        +----+---------------------+    
        | 1  |   1,1,1,1,1,1,...   |
        +----+---------------------+

我找不到我做错了什么.有人可以帮忙解决这个查询吗?或者指出我正确的方向?谢谢.

I cant find what I am doing wrong. Could someone help with this query? Or point me to a right direction? Thank you.

推荐答案

您缺少子查询中的条件.

You are missing the condition inside the sub query.

SELECT t2.Id, STUFF((SELECT ',' + CAST(VALUE AS varchar) FROM @MyTable t1  where t1.Id =t2.ID FOR XML PATH('')), 1 ,1, '') AS ValueList
FROM @MyTable t2
GROUP BY t2.Id

演示

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