并不是很困难：

;WITH cte AS
(
    SELECT CAST('/' + Name AS VARCHAR(50)) as 'CteName', ID
    FROM dbo.YourTable
    WHERE parent_id IS NULL

    UNION ALL

    SELECT CAST(cte.CteName + '/' + Name AS VARCHAR(50)), t.ID
    FROM dbo.YourTable t
    INNER JOIN cte ON t.parent_id = cte.id
)
SELECT cteName FROM cte
ORDER BY ID

为我提供以下输出：

/A
/A/B
/A/B/C
/A/D

作为旁注：深度可由CTE轻松计算，您不一定需要将其存储在表中（请参阅我添加的级别列d）：

As a side-note: the "depth" could be easily computed by the CTE and you don't necessarily need to store that in your table (see the Level column I've added):

;WITH cte AS
(
    SELECT 
       CAST('/' + Name AS VARCHAR(50)) as 'CteName', ID, 
       1 AS 'Level'
    FROM dbo.YourTable
    WHERE parent_id IS NULL

    UNION ALL

    SELECT 
       CAST(cte.CteName + '/' + Name AS VARCHAR(50)), t.ID,
       cte.Level + 1 AS 'Level'
    FROM dbo.YourTable t
    INNER JOIN cte ON t.parent_id = cte.id
)
SELECT cteName FROM cte
ORDER BY Level, ID