MySQL 8.0

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create table countries_hierarchy  (id int, parent_id int, place_name varchar(100))

insert into countries_hierarchy values(18,null,'Europe')
insert into countries_hierarchy values(9,18,'Germany')
insert into countries_hierarchy values(2,9,'Berlin')
insert into countries_hierarchy values(4,9,'Frankfurt')
with recursive cte(place_name,id,parent_id,level)
  as (select place_name,id,parent_id,1 as level
        from countries_hierarchy
       where parent_id is null
       union all
       select concat(lpad(' ',a.level+1,' ')
                    ,b.place_name
                    )
              ,b.id
              ,b.parent_id
              ,a.level+1
         from cte a
         join countries_hierarchy b
           on a.id=b.parent_id
       )
select * from cte       


place_name
id
parent_id
level


Europe
18
null
1

  Germany
9
18
2

   Berlin
2
9
3

   Frankfurt
4
9
3