Hierarchical data run infinitely in SQL Server 2008 - sql-server

Question

I am using SQL Server 2008.In my databse one table like:
------------------------------
id parentId name
------------------------------
1 NULL india
2 1 gujrat
3 1 Maharastra
4 1 rajsthan
5 2 ahmedabad
6 2 rajkot
7 NULL USA
8 7 newyork
1 3 mumbai
1 3 goa
1 4 jaipur
1 7 californiya
Here i want to get this data with it's level in hierarchy, so i create query like:
with RecursiveTable_CTE (Id,Parentid,Name_cte,Hlevel)
as
(
select id , parentId, name, 0 as Hlevel from treeTable where id = 1
union all
select t.id,t.parentId,t.name, Hlevel + 1 as LEVEL from treeTable as t inner join RecursiveTable_CTE as rtc on t.id = rtc.Parentid
)
select * from RecursiveTable_CTE option (maxrecursion 0)
and also try
with RecursiveTable_CTE (Id,Parentid,Name_cte,Hlevel)
as
(
select id , parentId, name, 0 as Hlevel from treeTable where parentId is null
union all
select t.id,t.parentId,t.name, Hlevel + 1 as LEVEL from treeTable as t inner join RecursiveTable_CTE as rtc on rtc.id = t.parentId
)
select * from RecursiveTable_CTE option (maxrecursion 0)
but both result infinite loop.
can any one help me?

Answer 1

I think the query you're after is this:
with RecursiveTable_CTE (Id,Parentid,Name_cte,Hlevel)
as
(
select id , parentId, name, 0 as Hlevel
from treeTable
where parentId is null
union all
select t.id,t.parentId,t.name, rtc.Hlevel + 1 as Hlevel
from treeTable as t
inner join RecursiveTable_CTE as rtc on t.Parentid = rtc.id
)
select * from RecursiveTable_CTE
The problem is though that I think your data is not correct and id and parentId are swapped in some rows. I used this data:
insert into treeTable values (1, NULL, 'india')
insert into treeTable values (2, 1, 'gujrat')
insert into treeTable values (3, 1, 'Maharastra')
insert into treeTable values (4, 1, 'rajsthan')
insert into treeTable values (5, 2, 'ahmedabad')
insert into treeTable values (6, 2, 'rajkot')
insert into treeTable values (7, NULL, 'USA')
insert into treeTable values (8, 7 , 'newyork')
insert into treeTable values (9, 1 , 'mumbai')
insert into treeTable values (10, 1 , 'goa')
insert into treeTable values (11, 1 , 'jaipur')
insert into treeTable values (12, 7 , 'californiya')
SQL Fiddle demo

Answer 2

Here in your case ther 1 is top level but again 1 has parents 3,4,7.
your infinite loop is due to your wrong herarchy.
id parentId name
------------------------------
1 NULL india
1 3 mumbai
1 4 jaipur
1 7 californiya

Answer 3

You have duplicates in the ID column, Is that a typo? If you don't have duplicates
CREATE TABLE states
(
[id] INT,[parentid] INT,[name] VARCHAR(11)
);
INSERT INTO states
([id],[parentid],[name])
VALUES (1,NULL,'india'),
(2,1,'gujrat'),
(3,1,'Maharastra'),
(4,1,'rajsthan'),
(5,2,'ahmedabad'),
(6,2,'rajkot'),
(7,NULL,'USA'),
(8,7,'newyork'),
(9,3,'mumbai'),
(10,3,'goa'),
(11,4,'jaipur'),
(12,7,'californiya');
WITH recursivetable_cte (id, parentid, name_cte, hlevel)
AS (SELECT id,parentid,name,0 AS Hlevel
FROM states
WHERE parentid IS NULL
UNION ALL
SELECT t.id,t.parentid,t.name,hlevel + 1 AS LEVEL
FROM states AS t
INNER JOIN recursivetable_cte AS rtc
ON t.parentid = rtc.id)
SELECT *
FROM recursivetable_cte
OPTION (maxrecursion 0)

Answer 4

#Szymom is right.id should be unique.though in this query no need of changing table data
see the change,
;with RecursiveTable_CTE (Id,Parentid,Name_cte,Hlevel)
as
(
select id , parentId, name, 0 as Hlevel from #t where id = 1 **and parentId is null**
union all
select t.id,t.parentId,t.name, Hlevel+ 1 as LEVEL from #t as t
inner join RecursiveTable_CTE as rtc on t.Parentid = rtc.id **and t.id<>1**
)
select * from RecursiveTable_CTE