> On 26 Jul 2021, at 17:52, Alban Hertroys <haramrae@gmail.com> wrote:
> Something like this:
>
> with recursive foo (id, parent, children_ids) as (
> select id, parent, null::text
> from tree t
> where not exists (
> select 1 from tree c where c.parent = t.id
> )
> union all
> select t.id, t.parent
> , f.id || case f.children_ids when '' then '' else ',’ end || f.children_ids
> from foo f
> join tree t on f.parent = t.id
> where f.parent <> 0
> ;
Almost, the null::text in the initial select should of course be '’ in your case, and a unicode quote slipped into the
laststring of that case statement.
Alban Hertroys
--
If you can't see the forest for the trees,
cut the trees and you'll find there is no forest.
