分层数据在SQL Server 2008中无限运行

Question

我正在使用SQL Server 2008.在我的数据库中，一个表如下：

------------------------------
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

在这里，我想用层次结构中的级别获取此数据，因此我创建了如下查询：

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)

并尝试

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)

但都导致无限循环。

谁能帮我？

Answer 1

我认为你追求的问题是这样的：

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

问题是，我认为您的数据不正确，并且id和parentId在某些行中交换。 我用过这个数据：

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小提琴演示

Answer 2

在你的情况下，1是顶级，但1又有父3,7,7。
你的无限循环是由于你错误的层次结构。

id   parentId   name
------------------------------
1    NULL       india
1    3          mumbai
1    4          jaipur
1    7          californiya

Answer 3

您在ID列中有重复项，这是一个错字吗？ 如果你没有重复

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是对的.id应该是唯一的。虽然在这个查询中不需要更改表数据

看到变化，

;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