无限极分类查询

From:http://www.cnblogs.com/smailxiaobai/archive/2012/01/13/2321850.html

--建立一个数据表 这可以是你的一个物理表

declare @temp table(
    ID varchar(20),
    ParentID varchar(20),
    Name nvarchar(100))

insert into @temp values('A','','分类A')
insert into @temp values('B','','分类B')
insert into @temp values('C','','分类C')
insert into @temp values('D','','分类D')
insert into @temp values('A1','A','分类A1')
insert into @temp values('A2','A','分类A2')
insert into @temp values('A11','A1','分类A11')
insert into @temp values('A12','A1','分类A12')

select * from @temp

--查询"分类A"下面的所有数据
declare @$result table(
    ID  varchar(20), 
    ParentID  varchar(20), 
    Name nvarchar(100),
    myLevel  int)
declare @Level int
set @Level = 0
insert into @$result select *,@Level from @temp where ID='A'

while(@@rowcount>0)
begin
    set @Level = @Level + 1
    insert into @$result 
    select a.*,@Level 
    from @temp a,@$result b
    where a.ParentID = b.ID and myLevel = @Level-1
end
select * from @$result

关键就是设一个标志Level进行轮询查找出想要的数据。

查询分类表字段修改成如下：
cataid,catatitle,parentid,orderid


DECLARE @ProductCenterCatalogID int
SET @ProductCenterCatalogID=2;
WITH ACTE(cataid,catatitle,orderid,parentid)
AS
( 
SELECT cataid,catatitle,orderid,parentid
FROM cata WHERE cataid=@ProductCenterCatalogID 
UNION ALL
SELECT TA.cataid,TA.catatitle,TA.orderid,TA.parentid
FROM cata TA INNER JOIN ACTE TB
ON TA.parentid=TB.cataid 
)
SELECT cataid,catatitle,orderid,parentid FROM ACTE order by parentid,orderid