SQL递归函数列出父级的所有子级(ID ParentID模式)

1. --调用方法：
   --select * from GetChild('24')
   --select id from GetChild('24')
   --select * from KuCun where ProductType in(select id from GetChild('24'))
   
   Create function [dbo].[GetChild](@ID varchar(10))
   returns @t table(ID varchar(10),ParentID varchar(10),Level int)
   as
   begin
       declare @i int
       set @i = 1
       insert into @t select @ID,@ID,0 --当前级，本级，如果不要的话可以注释掉或再加个参数来选择操作
       insert into @t select ID,ParentID,@i from Dept where ParentID = @ID
   
       while @@rowcount<>0
       begin
           set @i = @i + 1
           insert into @t
           select
               a.ID,a.ParentID,@i
           from
               Dept a,@t b
           where
               a.ParentID=b.ID and b.Level = @i-1
       end
       return
   end
   
   --------------------------------------------------------------------------------
   --在SQL Server2005中其实提供了CTE[公共表表达式]来实现递归:
   Declare @Id Int
   Set @Id = 24;    ---在此修改父节点
   
   With RootNodeCTE(Id,ParentId)
   As
   (
   Select Id,ParentId From Dept Where ParentId In (@Id)
   Union All
   Select Dept.Id,Dept.ParentId From RootNodeCTE
   Inner Join Dept
   On RootNodeCTE.Id = Dept.ParentId
   )
   
   Select * From RootNodeCTE
   
   --------------------------------------------------------------------------------
   --------------------------------------------------------------------------------
   --------------------------------------------------------------------------------
   
   --生成测试数据
   create table Dept(ID int,ParentID int,msg varchar(20))
   insert into Dept select 1,0,null
   insert into Dept select 2,1,null
   insert into Dept select 3,1,null
   insert into Dept select 4,2,null
   insert into Dept select 5,3,null
   insert into Dept select 6,5,null
   insert into Dept select 7,6,null
   go
   
   
   --创建用户定义函数
   Create function [dbo].[GetChild](@ID varchar(10))
   returns @t table(ID varchar(10),ParentID varchar(10),Level int)
   as
   begin
       declare @i int
       set @i = 1
       insert into @t select @ID,@ID,0 --当前级，本级，如果不要的话可以注释掉或再加个参数来选择操作
       insert into @t select ID,ParentID,@i from Dept where ParentID = @ID
   
       while @@rowcount<>0
       begin
           set @i = @i + 1
           insert into @t
           select
               a.ID,a.ParentID,@i
           from
               Dept a,@t b
           where
               a.ParentID=b.ID and b.Level = @i-1
       end
       return
   end
   
   
   --执行查询
   select ID from dbo.GetChild(3)
   go
   
   --输出结果
   /*
   3
   5
   6
   7
   */
   
   --删除测试数据
   drop function GetChild
   drop table Dept
   
   --http://topic.csdn.net/u/20080409/16/1fb7d941-b1a1-4326-a936-230ddf057cbe.html

   --调用方法：
   --select * from GetChild('24')
   --select id from GetChild('24')
   --select * from KuCun where ProductType in(select id from GetChild('24'))
   
   Create function [dbo].[GetChild](@ID varchar(10))
   returns @t table(ID varchar(10),ParentID varchar(10),Level int)
   as
   begin
       declare @i int
       set @i = 1
       insert into @t select @ID,@ID,0 --当前级，本级，如果不要的话可以注释掉或再加个参数来选择操作
       insert into @t select ID,ParentID,@i from Dept where ParentID = @ID
   
       while @@rowcount<>0
       begin
           set @i = @i + 1
           insert into @t
           select
               a.ID,a.ParentID,@i
           from
               Dept a,@t b
           where
               a.ParentID=b.ID and b.Level = @i-1
       end
       return
   end
   
   --------------------------------------------------------------------------------
   --在SQL Server2005中其实提供了CTE[公共表表达式]来实现递归: 
   Declare @Id Int 
   Set @Id = 24;    ---在此修改父节点 
   
   With RootNodeCTE(Id,ParentId) 
   As 
   ( 
   Select Id,ParentId From Dept Where ParentId In (@Id) 
   Union All 
   Select Dept.Id,Dept.ParentId From RootNodeCTE 
   Inner Join Dept
   On RootNodeCTE.Id = Dept.ParentId 
   ) 
   
   Select * From RootNodeCTE
   
   --------------------------------------------------------------------------------
   --------------------------------------------------------------------------------
   --------------------------------------------------------------------------------
   
   --生成测试数据
   create table Dept(ID int,ParentID int,msg varchar(20))
   insert into Dept select 1,0,null
   insert into Dept select 2,1,null
   insert into Dept select 3,1,null
   insert into Dept select 4,2,null
   insert into Dept select 5,3,null
   insert into Dept select 6,5,null
   insert into Dept select 7,6,null
   go
   
   
   --创建用户定义函数
   Create function [dbo].[GetChild](@ID varchar(10))
   returns @t table(ID varchar(10),ParentID varchar(10),Level int)
   as
   begin
       declare @i int
       set @i = 1
       insert into @t select @ID,@ID,0 --当前级，本级，如果不要的话可以注释掉或再加个参数来选择操作
       insert into @t select ID,ParentID,@i from Dept where ParentID = @ID
   
       while @@rowcount<>0
       begin
           set @i = @i + 1
           insert into @t
           select
               a.ID,a.ParentID,@i
           from
               Dept a,@t b
           where
               a.ParentID=b.ID and b.Level = @i-1
       end
       return
   end
   
   
   --执行查询
   select ID from dbo.GetChild(3)
   go
   
   --输出结果
   /*
   3
   5
   6
   7
   */
   
   --删除测试数据
   drop function GetChild
   drop table Dept
   
   

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   怎么实现获取指定ID下的所有子级(sql2005)

2. 怎么实现获取指定ID下的所有子级(sql2005)

    

   Sql代码  

     www.2cto.com  

   create table tb(id varchar(3) , pid varchar(3) , name nvarchar(10))  

   insert into tb values('001' , null , N'广东省')  

   insert into tb values('002' , '001' , N'广州市')  

   insert into tb values('003' , '001' , N'深圳市')  

   insert into tb values('004' , '002' , N'天河区')  

   insert into tb values('005' , '003' , N'罗湖区')  

   insert into tb values('006' , '003' , N'福田区')  

   insert into tb values('007' , '003' , N'宝安区')  

   insert into tb values('008' , '007' , N'西乡镇')  

   insert into tb values('009' , '007' , N'龙华镇')  

   insert into tb values('010' , '007' , N'松岗镇')  

   go  

     

   DECLARE @ID VARCHAR(3)  

     

   --查询ID = '001'的所有子节点    www.2cto.com  

   SET @ID = '001'  

   ;WITH T AS  

   (  

   SELECT ID , PID , NAME   

   FROM TB  

   WHERE ID = @ID  

   UNION ALL  

   SELECT A.ID , A.PID , A.NAME   

   FROM TB AS A JOIN T AS B ON A.PID = B.ID  

   )  

   SELECT * FROM T ORDER BY ID  

   /*  

   ID PID NAME  

   ---- ---- ----------  

   001 NULL 广东省  

   002 001 广州市  

   003 001 深圳市  

   004 002 天河区  

   005 003 罗湖区  

   006 003 福田区  

   007 003 宝安区  

   008 007 西乡镇  

   009 007 龙华镇  

   010 007 松岗镇  

     

   (10 行受影响)  

   */  

     

   --查询ID = '002'的所有子节点  

   SET @ID = '002'  

   ;WITH T AS  

   (  

   SELECT ID , PID , NAME   

   FROM TB  

   WHERE ID = @ID  

   UNION ALL  

   SELECT A.ID , A.PID , A.NAME   

   FROM TB AS A JOIN T AS B ON A.PID = B.ID  

   )  

   SELECT * FROM T ORDER BY ID  

   /*  

   ID PID NAME  

   ---- ---- ----------  

   002 001 广州市  

   004 002 天河区  

     

   (2 行受影响)  

   */  

     

   --查询ID = '003'的所有子节点  

   SET @ID = '003'  

   ;WITH T AS  

   (  

   SELECT ID , PID , NAME   

   FROM TB  

   WHERE ID = @ID  

   UNION ALL  

   SELECT A.ID , A.PID , A.NAME   

   FROM TB AS A JOIN T AS B ON A.PID = B.ID  

   )  

   SELECT * FROM T ORDER BY ID  

   /*  

   ID PID NAME  

   ---- ---- ----------  

   003 001 深圳市  

   005 003 罗湖区  

   006 003 福田区  

   007 003 宝安区  

   008 007 西乡镇  

   009 007 龙华镇  

   010 007 松岗镇  

     

   (7 行受影响)  

   */  

     

   drop table tb  

     

   --注：除ID值不一样外，三个SQL语句是一样的。