DECLARE @t TABLE(id INT ,NAME VARCHAR(10),parentid INT);

INSERT INTO @t (id,name,parentid)VALUES 
(1,'A',0)
,(2,'B',0)
,(3,'A1',1)
,(4,'A2',1)
,(5,'B1',2)
,(6,'C1',1)

;WITH cte AS (
    SELECT *,1 AS l,rn=ROW_NUMBER() OVER(ORDER BY id) FROM @t WHERE parentid=0 
    UNION ALL 
    SELECT a.*,b.l+1,rn=b.rn*10+ROW_NUMBER() OVER(ORDER BY a.id) FROM @t a JOIN cte b ON a.parentid=b.id
)
SELECT id,REPLICATE('-',l)+name AS name FROM cte ORDER BY CAST(rn AS varchar(1000));

/*
id          name
----------- ---------
1           -A
3           --A1
4           --A2
6           --C1
2           -B
5           --B1

*/