Re: Is there any chance to get some kind of a result set sifting mechanism in Postgres?

Hi,
If you call the action of "sifting" ordering, then yes. If you don't call
it ordering, then no.

In essence, is the output of a filtering mechanism, done in a single result
set pass. And this pass should be the same pass in charge of collecting the
result set in the first place.

Thanks

On Mon, May 13, 2024 at 5:48 AM Wolfgang Wilhelm <wolfgang20121964(at)yahoo(dot)de>
wrote:

> Hi,
>
> do I interpret your idea correctly: You want some sort of ordering without
> ordering?
>
> Kind regards
> WW
>
> Am Montag, 13. Mai 2024 um 10:40:38 MESZ hat aa <ghevge(at)gmail(dot)com>
> Folgendes geschrieben:
>
>
> Hello Everyone!
>
> Is there any chance to get some kind of a result set sifting mechanism in
> Postgres?
>
> What I am looking for is a way to get for example: "nulls last" in a
> result set, without having to call "order by" or having to use UNION ALL,
> and if possible to get this in a single result set pass.
>
> Something on this line: SELECT a, b, c FROM my_table WHERE a nulls last
> OFFSET 0 LIMIT 25
>
> I don't want to use order by or union all because these are time consuming
> operations, especially on large data sets and when comparations are done
> on dynamic values (eg: geolocation distances in between a mobile and a
> static location)
>
> What I would expect from such a feature, will be speeds comparable with
> non sorted selects, while getting a very rudimentary ordering.
>
> A use case for such a mechanism will be the implementation of QUICK
> relevant search results for a search engine.
>
> I'm not familiar with how Postgres logic handles simple select queries,
> but the way I would envision a result set sifting logic, would be to
> collect the result set, in 2 separate lists, based on the sifting
> condition, and then concatenate these 2 lists and return the result, when
> the pagination requests conditions are met.
>
> Any idea if such a functionality is feasible ?
>
> Thank you.
>
> PS: if ever implemented, the sifting mechanism could be extended to
> accommodate any type of thresholds, not just null values.
>
>
>
>