Re: nextval per counted

On 1/27/23 14:20, David G. Johnston wrote:
> On Fri, Jan 27, 2023 at 1:59 PM Rob Sargent <robjsargent(at)gmail(dot)com> wrote:
>
> I'm trying to craft SQL to invoke a sequence nextval once per
> grouped value.
>
>
> This seems like a very unusual usage of nextval/sequences...
>
> with cleanup as (
>   select DISTINCT e.ma <http://e.ma>, coalesce(e.pa <http://e.pa>,
> 'fix') as pa from ...
> ), compute as (
>   select ma, pa, nextval(...) from cleanup
> )
> select * from compute ... -- do whatever else you want
>
> So far I have this:
>
> with husb as(
> select e.ma <http://e.ma>, count(distinct coalesce(e.pa
> <http://e.pa>, nextval('egogen')::text)) as mates
> from emp_all_by3 e group by e.ma <http://e.ma> order by mates
> )
> select mates, count(*)
> from husb
> group by mates order by mates desc;
>
> Your "order by mates" in the CTE is totally pointless and wasting
> resources.
>
> David J.
>
Yeah, it wasn't when that was the last bit executed...

Seems asking a sequence for an id isn't too unusual?  Or are they
specifically intended for primary keys?