WITH t_model (id,parent_name, product_name,lvl) as (
      SELECT 1,NULL,'КЭ01',1 FROM DUAL UNION ALL
      SELECT 2,'КЭ01','КЭ02',2 FROM DUAL UNION ALL
      SELECT 3,'КЭ01','КЭ03',2 FROM DUAL UNION ALL
      SELECT 4,'КЭ02','КЭ04',3 FROM DUAL UNION ALL
      SELECT 5,'КЭ02','КЭ05',3 FROM DUAL  
)      
select rpad('-',level,'--')||'>'||product_name as p from t_model
start with .... 
connect by prior ...
;

-- table 1 with column list
with user_tab(user_id,user_name,registry_date) as (
select 1,'Bob',to_date('11.02.1921 23:04:44','DD.MM.YYYY HH24:MI:SS') from dual union all
select 2,'Max',to_date('11.02.1922 23:04:44','DD.MM.YYYY HH24:MI:SS') from dual union all
select 3,'Jon',to_date('11.02.1923 23:04:44','DD.MM.YYYY HH24:MI:SS') from dual
)
-- table 2 with column list
,user_post(post_id,user_id,parent_post_id,post_date,message) as (
select 100,1,null,to_date('11.02.1923 23:04:00','DD.MM.YYYY HH24:MI:SS'),'Hi' from dual union all
select 101,2,100,to_date('11.02.1923 23:05:23','DD.MM.YYYY HH24:MI:SS'),'Hi' from dual union all
select 102,3,100,to_date('11.02.1923 23:05:35','DD.MM.YYYY HH24:MI:SS'),'Hi' from dual union all
select 103,1,102,to_date('11.02.1923 23:06:00','DD.MM.YYYY HH24:MI:SS'),'How are you' from dual union all
select 104,2,102,to_date('11.02.1923 23:07:05','DD.MM.YYYY HH24:MI:SS'),'All right!' from dual union all
select 105,1,101,to_date('11.02.1923 23:06:21','DD.MM.YYYY HH24:MI:SS'),'Bye' from dual union all
select 106,1,104,to_date('11.02.1923 23:04:37','DD.MM.YYYY HH24:MI:SS'),'Bye' from dual union all
select 107,2,null,to_date('11.02.1923 23:08:56','DD.MM.YYYY HH24:MI:SS'),'Hmm' from dual
)
-- query sample
select

-- level
-- ,u.user_name
-- ,p.message
rpad(to_char(p.post_date,'YYYY-MM-DD HH24:MI:SS  '),20+level*2,' ')||u.user_name||': '||p.message as txt
from 
 user_post p
 join user_tab  u on ( p.user_id = u.user_id)
where p.post_date >= u.registry_date
start with p.parent_post_id is null 
connect by prior p.post_id=p.parent_post_id 
;