Requête récursive t-sql

Question

Sur la base d'une table existante, j'ai utilisé la requête récursive CTE pour trouver les données suivantes. Mais ne pas l'appliquer un niveau plus loin.

données est comme ci-dessous

id name  parentid 
-------------------------- 
1  project 0 
2  structure 1 
3  path_1 2 
4  path_2 2 
5  path_3 2 
6  path_4 3 
7  path_5 4 
8  path_6 5 

Je veux former récursive chemins complets à partir des données ci-dessus. Signifie que la récursivité donnera la sortie suivante.

FullPaths 
------------- 
Project 
Project\Structure 
Project\Structure\Path_1 
Project\Structure\Path_2 
Project\Structure\Path_3 
Project\Structure\Path_1\path_4 
Project\Structure\Path_2\path_5 
Project\Structure\Path_3\path_6 

Merci

Answer 1

Voici un exemple CTE à faire:

declare @t table (id int, name varchar(max), parentid int) 

insert into @t select 1,  'project' , 0 
union all select 2,  'structure' , 1 
union all select 3,  'path_1' , 2 
union all select 4,  'path_2' , 2 
union all select 5,  'path_3' , 2 
union all select 6,  'path_4' , 3 
union all select 7,  'path_5' , 4 
union all select 8,  'path_6' , 5 

; with CteAlias as (
    select id, name, parentid 
    from @t t 
    where t.parentid = 0 
    union all 
    select t.id, parent.name + '\' + t.name, t.parentid 
    from @t t 
    inner join CteAlias parent on t.parentid = parent.id 
) 
select * 
from CteAlias 

Answer 2

Quelque chose comme

;WITH MyCTE AS 
(
    SELECT 
     name AS FullPaths, id 
    FROM 
     MyTable 
    WHERE 
     parentid = 0 /*Normally it'd be IS NULL with an FK linking the 2 columns*/ 
    UNION ALL 
    SELECT 
     C.FullPaths + '\' + M.name, M.id 
    FROM 
     MyCTE C 
     JOIN 
     MyTable M ON M.parentid = C.id 
) 
SELECT FullPaths FROM MyCTE 

Answer 3

essayez ceci:

DECLARE @YourTable table (id int, nameof varchar(25), parentid int) 
INSERT @YourTable VALUES (1,'project',0) 
INSERT @YourTable VALUES (2,'structure',1) 
INSERT @YourTable VALUES (3,'path_1',2) 
INSERT @YourTable VALUES (4,'path_2',2) 
INSERT @YourTable VALUES (5,'path_3',2) 
INSERT @YourTable VALUES (6,'path_4',3) 
INSERT @YourTable VALUES (7,'path_5',4) 
INSERT @YourTable VALUES (8,'path_6',5) 

;WITH Rec AS 
(
    SELECT 
     CONVERT(varchar(max),nameof) as nameof,id 
     FROM @YourTable 
     WHERE parentid=0 
    UNION ALL 
    SELECT 
     CONVERT(varchar(max),r.nameof+'\'+y.nameof), y.id 
     FROM @yourTable y 
      INNER jOIN Rec r ON y.parentid=r.id 
) 
select * from rec 

sortie:

nameof           
----------------------------------------------- 
project           
project\structure        
project\structure\path_1      
project\structure\path_2      
project\structure\path_3      
project\structure\path_3\path_6     
project\structure\path_2\path_5     
project\structure\path_1\path_4     

(8 row(s) affected) 

Answer 4

Essayez quelque chose comme ceci:

WITH Recursive AS 
(
    SELECT 
     ID, 
      CAST(PathName AS VARCHAR(500)) AS 'FullPaths', 
      1 AS 'Level' 
    FROM 
     dbo.YourTable 
    WHERE 
     ParentID = 0 

    UNION ALL 

    SELECT 
     tbl.ID, 
      CAST(r.FullPaths + '\' + tbl.PathName AS VARCHAR(500)) AS 'FullPaths', 
      r.Level + 1 AS 'Level' 
    FROM 
     dbo.YourTable tbl 
    INNER JOIN 
     Recursive r ON tbl.ParentID = r.ID 
) 
SELECT * FROM Recursive 
ORDER BY Level, ID 

Sortie:

ID FullPaths     Level 
1 project       1 
2 project\structure     2 
3 project\structure\path_1   3 
4 project\structure\path_2   3 
5 project\structure\path_3   3 
6 project\structure\path_1\path_4 4 
7 project\structure\path_2\path_5 4 
8 project\structure\path_3\path_6 4 

Answer 5

Vous devez changer le nom de la table #test j'utilisais.

WITH cte(id, name, parentid) AS 
(
    SELECT id, convert(varchar(128), name), parentid 
    FROM #test 
    WHERE parentid = 0 
    UNION ALL 
    SELECT t.id, convert(varchar(128), c.name +'\'+t.name), t.parentid 
    FROM #test t 
    INNER JOIN cte c 
    ON c.id = t.parentid 
) 
SELECT name as FullPaths 
FROM cte 
order by id