Realmente no es tan difícil de hacer:
;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
me da una salida de:
/A
/A/B
/A/B/C
/A/D
Como nota al margen:el CTE podría calcular fácilmente la "profundidad" y no necesariamente necesita almacenar eso en su tabla (consulte el Level
columna que he agregado):
;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