Combining several CTEs with a recursive CTE

Hello all,

this is more a "just curious" question, rather than a real world problem.

We can combine several CTEs into a single select using something like this:

WITH cte_1 as (   select ....
),
cte_2 as (   select ...   where id (select some_col from cte_1)
)
select *
from cte_2;


But this does not seem to work when a recursive CTE is involved


WITH cte_1 as (   select ....
),
recursive cte_2 as (   select ...   where id (select some_col from cte_1)
   union all
   select ...
)
select *
from cte_2;

This throws an error: syntax error at or near "cte_2"

I'm just wondering if this is intended behavioury, simply not (yet) implemented or even invalid according to the
standard?I didn't find any reference that it's not allowed in the manual.
 

Regards
Thomas