* Richard Broersma Jr <rabroersma@yahoo.com> [221106, 15:30]:
>
> > -----------------------------------
> >
> > PS: I didn't go through all pg-documentation so my guess might be a bit
> > of hazard: shouldn't the 'distinct on (some_field)' do all the job on its own
> > with no need for the second (sub)select? Otherwise there seems to be no
> > difference between 'select distinct on (fx) f1, f2, .,fx,. ,fn' and
> > 'select distinct f1, f2, .,fx,. fn'.
> >
>
> I think that distinct on works like a where clause. So if filter out records rather than grouping
> them. So you end up with a sum of 1 record.
>
> Regards,
>
> Richard Broersma jr.
Thank you, Richard, for this further element of knowledge!
In the meantime I've tested the real table and your query works like a
charm: now, finally, my nice (coloured) summary table tells the 'truth' :-)))
Cheers,
Ennio
--
[Perche' usare Win$ozz (dico io) se ..."anche uno sciocco sa farlo. \\?//
Fa' qualche cosa di cui non sei capace!" (diceva Henry Miller) ] (°|°)
[Why use Win$ozz (I say) if ... "even a fool can do that. )=(
Do something you aren't good at!" (as Henry Miller used to say) ]
