Sql server 如何将T-SQL CTE查询中的uniqueidentifier ID组合成字符串

我想在T-SQL CTE查询中生成带有逗号分隔为字符串的

uniqueidentifier

ID：

WITH departmentcte(ID, Name, ParentID, LEVEL, FullPath) AS
( 
    SELECT 
        ID, Name, ParentID, 0 AS LEVEL, 
        CAST(Name AS VARCHAR(1024)) AS FullPath 
    FROM 
        ItemModels 
    WHERE 
        ParentID IS NULL

    UNION ALL  

    SELECT 
        d.ID, d.Name, d.ParentID, departmentcte.LEVEL + 1 AS LEVEL,
        CAST(departmentcte.FullPath + '\' + CAST(d.Name AS VARCHAR(1024)) AS VARCHAR(1024)) AS FullPath  
    FROM 
        ItemModels d
    INNER JOIN 
        departmentcte ON departmentcte.ID = d.ParentID
)
SELECT ID, Name, FullPath  
FROM departmentcte;

它按预期返回此结果：

但是我想得到一个子集的所有ID，比如

所以我尝试下面的查询，我得到了错误

“子ID”中绑定部分和递归部分之间的类型不匹配 递归“departmentcte”查询的列

---

正如我看到的，SubIDs具有nvarchar数据类型，那么问题出在哪里呢？

多亏了我找到的所有解决方案

    WITH departmentcte(ID,ParentID, LEVEL, FullPath, SubIDs) AS
    ( SELECT ID,  ParentID, 0 AS LEVEL, CAST(Name AS VARCHAR(1024)) AS FullPath, convert(varchar(2048), ID) as SubIDs 
        FROM ItemModels WHERE ParentID IS NULL
     UNION ALL  
     SELECT d.ID,  d.ParentID, departmentcte.LEVEL + 1 AS LEVEL, 
          CAST(        departmentcte.FullPath  + ','  + CAST(d.Name AS VARCHAR(1024)) AS VARCHAR(1024)) AS FullPath,      
          CAST( ISNULL(departmentcte.SubIDs,'') + ',' + convert(nvarchar(36), d.ID)  AS VARCHAR(2048))  AS SubIDs 
     FROM ItemModels d INNER JOIN departmentcte ON departmentcte.ID = d.ParentID)

SELECT *  FROM departmentcte;

其思想是在

UNION ALL

的两个字段中使用相同大小的

varchar/nvarchar

。

---

在我的例子中，它是

varchar（2048）

，我正要发布一个与此非常类似的答案。顺便说一下，下次您询问时，请提供演示链接或一些示例数据。对于你上面提出的问题，大多数人帮不了你多少忙。

    WITH departmentcte(ID,ParentID, LEVEL, FullPath, SubIDs) AS
    ( SELECT ID,  ParentID, 0 AS LEVEL, CAST(Name AS VARCHAR(1024)) AS FullPath, convert(varchar(2048), ID) as SubIDs 
        FROM ItemModels WHERE ParentID IS NULL
     UNION ALL  
     SELECT d.ID,  d.ParentID, departmentcte.LEVEL + 1 AS LEVEL, 
          CAST(        departmentcte.FullPath  + ','  + CAST(d.Name AS VARCHAR(1024)) AS VARCHAR(1024)) AS FullPath,      
          CAST( ISNULL(departmentcte.SubIDs,'') + ',' + convert(nvarchar(36), d.ID)  AS VARCHAR(2048))  AS SubIDs 
     FROM ItemModels d INNER JOIN departmentcte ON departmentcte.ID = d.ParentID)

SELECT *  FROM departmentcte;