SQL Server 2005 CTE的用法

if object_id('[tb]') is not null
drop table [tb] 
go
create table [tb]([id] int,[col1] varchar(8),[col2] int) 
insert [tb] 
select 1,'河北省',0 union all
 select 2,'邢台市',1 union all
 select 3,'石家庄市',1 union all
 select 4,'张家口市',1 union all
 select 5,'南宫',2 union all 
select 6,'坝上',4 union all
  select 7,'任县',2 union all
 select 8,'清河',2 union all 
select 9,'河南省',0 union all
 select 10,'新乡市',9 union all
 select 11,'aaa',10 union all
 select 12,'bbb',10  
 
 ;with t as( 
select * from [tb] where col1='河北省'  union all  select a.* from [tb] a  ,t where a.col2=t.id   
)
 
 select * from t