SQL: Wie erstellt man eine Ansicht aus einer rekursiven Abfrage?

Question

Frage: Ich habe eine Sicht, die ich von einer rekursiven Abfrage ableiten möchte.

Die Abfrage ist die gleiche Struktur wie dieser hier: http://forums.asp.net/t/1207101.aspx

und stellt eine Baumansicht als eine geordnete Datenmenge.

Wie kann ich eine Ansicht, die dies tut:

;WITH Tree (ID, [NAME], PARENT_ID, Depth, Sort) AS 
(
    SELECT ID, [NAME], PARENT_ID, 0 AS Depth, CONVERT(varchar(255), [Name]) AS Sort FROM Category 
    WHERE PARENT_ID = 0 
    UNION ALL 
    SELECT CT.ID, CT.[NAME], CT.PARENT_ID, Parent.Depth + 1 AS Depth, 
    CONVERT(varchar(255), Parent.Sort + ' | ' + CT.[NAME]) AS Sort 
    FROM Category CT 
    INNER JOIN Tree as Parent ON Parent.ID = CT.PARENT_ID 
) 

-- HERE IS YOUR TREE, Depths gives you the level starting with 0 and Sort is the Name based path 
SELECT ID, [NAME], PARENT_ID, Depth, Sort FROM Tree 
ORDER BY Sort 

Answer 1

Es sollte so einfach sein wie:

CREATE VIEW YourViewName 
AS 
    WITH Tree (ID, [NAME], PARENT_ID, Depth, Sort) AS 
    (
     SELECT ID, [NAME], PARENT_ID, 0 AS Depth, CONVERT(varchar(255), [Name]) AS Sort   
     FROM Category 
     WHERE PARENT_ID = 0 
     UNION ALL 
     SELECT CT.ID, CT.[NAME], CT.PARENT_ID, Parent.Depth + 1 AS Depth, 
     CONVERT(varchar(255), Parent.Sort + ' | ' + CT.[NAME]) AS Sort 
     FROM Category CT 
     INNER JOIN Tree as Parent ON Parent.ID = CT.PARENT_ID 
    ) 

    -- HERE IS YOUR TREE, Depths gives you the level starting with 0 and Sort is the Name based path 
    SELECT ID, [NAME], PARENT_ID, Depth, Sort FROM Tree 
GO