How can i get the id of the last child record in hierarchical data

Question

I want to get the lastest child record  of the parents like 
the result   
If I Select A then the result should be  'C' , 'E' , 'F' , 'G'
If i select D then the result should be 'F' etc
Thanks
USE [SMEDB]
GO
/****** Object:  Table [dbo].[Table_3]    Script Date: 11/26/2014 2:10:49 PM ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TABLE [dbo].[Table_3](
[ID] [nvarchar](50) NULL,
[ParentID] [nvarchar](50) NULL
) ON [PRIMARY]
GO
INSERT [dbo].[Table_3] ([ID], [ParentID]) VALUES (N'A', NULL)
INSERT [dbo].[Table_3] ([ID], [ParentID]) VALUES (N'B', N'A')
INSERT [dbo].[Table_3] ([ID], [ParentID]) VALUES (N'C', N'D')
INSERT [dbo].[Table_3] ([ID], [ParentID]) VALUES (N'D', N'A')
INSERT [dbo].[Table_3] ([ID], [ParentID]) VALUES (N'E', N'D')
INSERT [dbo].[Table_3] ([ID], [ParentID]) VALUES (N'F', N'E')
INSERT [dbo].[Table_3] ([ID], [ParentID]) VALUES (N'G', N'A')

Answer 1

WITH cte(ID, ParentID, Lvl, HPath)
AS (
       SELECT ID,
              ParentID,
              0,
              CAST(ID AS VARCHAR(MAX)) + '\' AS HPath
       FROM   dbo.[Table_3]
       WHERE  ID ='D'
       UNION ALL
       SELECT        e.ID,
                     e.ParentID,
                     m.Lvl + 1 AS Lvl,
                     m.HPath +CAST(e.ID AS VARCHAR(MAX))+ '\'  AS HPath
       FROM          dbo.[Table_3] AS e
       INNER JOIN    cte AS m ON m.ID = e.ParentID
),cte1
AS
SELECT HPath,id,Parentid,lvl,
RIGHT(LEFT(HPath,LEN(HPath)-1),CHARINDEX('\',REVERSE(LEFT(HPath,LEN(HPath))))) lst
FROM   cte WHERE lvl>0
) SELECT lst FROM cte1 WHERE NOT EXISTS (SELECT * FROM cte1 c WHERE c.ParentID=cte1.lst)
Best Regards,Uri Dimant SQL Server MVP,
http://sqlblog.com/blogs/uri_dimant/
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