Sql 在不知道字符串长度的情况下删除其他逗号

我的桌子

我的桌子

dependentId

包含类似

14的值；77;120

---

MyDependentable

---

背景

我必须从

MyTable

中选择数据，其中

MyDependentTable

中的每个依赖项都用逗号分隔

预期产出：

+---------+-------------------------------------+
| Title   | Dependencies                        |
+---------+-------------------------------------+
| Test    | ABC, One-two-three, Some Dependency |
+---------+-------------------------------------+
| Example | ABC                                 |
+---------+-------------------------------------+

---

我的查询

SELECT t.Title,
    (SELECT ISNULL((
        SELECT DISTINCT
        (
            SELECT dt.Name + '',
                   CASE WHEN DependencyIds LIKE '%;%' THEN ', ' ELSE '' END AS [text()]
            FROM MyDependentTable dt
            WHERE dt.DependencyId IN (SELECT Value FROM dbo.fSplitIds(t.DependencyIds, ';'))
            ORDER BY dt.DependencyId
            FOR XML PATH('')
        )), '')) Dependencies
FROM dbo.MyTable t

---

问题描述

查询可以工作，但当存在多个依赖项时，会添加一个额外的逗号：

+---------+---------------------------------------+
| Title   | Dependencies                          |
+---------+---------------------------------------+
| Test    | ABC, One-two-three, Some Dependency,  |
+---------+---------------------------------------+
| Example | ABC                                   |
+---------+---------------------------------------+

我无法使用

子字符串（ISNULL（…

），因为我无法访问字符串的长度，因此无法设置

子字符串的长度

有没有可能去掉不必要的额外逗号？
通常对于Sql Server中的组连接，人们会添加前导逗号，然后使用
STUFF
函数将其删除，但即使这样看起来也很难看

Outer Apply
方法看起来很整洁，可以这样做，而不是
相关子查询
。在这种方法中，我们不必将
选择
查询包装为
ISNULL
或
内容

SELECT DISTINCT t.title, 
                Isnull(LEFT(dependencies, Len(dependencies) - 1), '') 
                Dependencies 
FROM   dbo.mytable t 
       OUTER apply (SELECT dt.NAME + ',' 
                    FROM   mydependenttable dt 
                    WHERE  dt.dependencyid IN (SELECT value 
                                               FROM 
                           dbo.Fsplitids(t.dependencyids,';')) 
                    ORDER  BY dt.dependencyid 
                    FOR xml path('')) ou (dependencies) 

下面是使用
STUFF
的方法

SELECT  t.Title
       ,STUFF((SELECT ', ' + CAST(dt.Name AS VARCHAR(10)) [text()]
               FROM MyDependentTable dt
               WHERE dt.DependencyId IN (SELECT Value FROM dbo.fSplitIds(t.DependencyIds, ';'))
               ORDER BY dt.DependencyId
               FOR XML PATH(''), TYPE).value('.','NVARCHAR(MAX)'),1,2,' ') Dependencies
FROM dbo.MyTable  t

SELECT DISTINCT t.title, 
                Isnull(LEFT(dependencies, Len(dependencies) - 1), '') 
                Dependencies 
FROM   dbo.mytable t 
       OUTER apply (SELECT dt.NAME + ',' 
                    FROM   mydependenttable dt 
                    WHERE  dt.dependencyid IN (SELECT value 
                                               FROM 
                           dbo.Fsplitids(t.dependencyids,';')) 
                    ORDER  BY dt.dependencyid 
                    FOR xml path('')) ou (dependencies) 

SELECT  t.Title
       ,STUFF((SELECT ', ' + CAST(dt.Name AS VARCHAR(10)) [text()]
               FROM MyDependentTable dt
               WHERE dt.DependencyId IN (SELECT Value FROM dbo.fSplitIds(t.DependencyIds, ';'))
               ORDER BY dt.DependencyId
               FOR XML PATH(''), TYPE).value('.','NVARCHAR(MAX)'),1,2,' ') Dependencies
FROM dbo.MyTable  t