with t (c,p) as ( 
  select 2,1 from dual 
), rec (c,p) as ( 
  select c,p from t 
  union all 
  select t.* from rec join t on rec.c = t.p 
) 
select * from rec

with t (c,p) as ( 
  select 2,1 from dual 
), rec (c,p) as ( 
  select c,p from t 
  union all 
  select t.c,t.p from rec join t on rec.c = t.p 
) 
select * from rec

select * from v$version