On Tue, Aug 3, 2021 at 8:40 AM Rockdale Green <rockdale(dot)green(at)gmail(dot)com>
wrote:
> can I do it in one query?
>
Yes.
> It might be just very simple and I have tried but somehow I am blocked.
>
>
The feature you need is a recursive CTE (WITH RECURSIVE clause). It
requires an initial row (which in this case is task 3, the only task that
doesn't appear as a task_order value) and a query to retrieve the next
row(s) using the information available in the previous iteration.
The documentation and/or online resources can walk you through the
specifics.
David J.