Re: Re: Is ORDER BY in sub-query preserved when outer query is only projection?

hi, maybe selecting the relevant fields to order-by alongside (next to) the
row()'ed part, they will be selected "twice", but you'll be able to
reference them.

regards

Haroldo

2018-01-14 9:40 GMT-03:00 Andreas Joseph Krogh <andreas(at)visena(dot)com>:

> På søndag 14. januar 2018 kl. 13:30:29, skrev Francisco Olarte <
> folarte(at)peoplecall(dot)com>:
>
> Andreas:
>
> On Sun, Jan 14, 2018 at 1:03 PM, Andreas Joseph Krogh
> <andreas(at)visena(dot)com> wrote:
> > SELECT q.* FROM (
> > SELECT comp.id, comp.name
> > FROM company comp JOIN req r ON r.company_id = comp.id
> > ORDER BY LOWER(comp.name) ASC
> > ) AS q
> > ORDER BY r.status ASC
> >
> > What I'm trying to do here is to order by some status (which may be only
> 1 of 3 values, for instance OPEN, IN_PROGRESS, CLOSED), then order by
> company-name so I get results for each status sorted by company-name.
> >
> > Is this kind of sort stable, can I assume the pre-sorted result's order
> is preserved so I achieve what I want?
>
> I doubt it is mandated to be stable. But IIRC you can sort by a
> non-returned field, so you should be able to do it in just one query (
> http://sqlfiddle.com/#!17/aaa62/3 )
>
> I would try
>
> SELECT comp.id, comp.name
> FROM company comp JOIN req r ON r.company_id = comp.id
> ORDER BY r.status ASC, LOWER(comp.name) ASC
>
> Francisco Olarte.
>
>
> Thanks, but my real query is more complex and I need to sort on a custom
> coposite type so I think I *need* an outer query for that, see my post
> here: http://www.postgresql-archive.org/ORDER-BY-custom-
> type-td6000437.html
>
> Do you see any solution sorting on a composite type without using an outer
> query?
>
> --
> *Andreas Joseph Krogh*
> CTO / Partner - Visena AS
> Mobile: +47 909 56 963
> andreas(at)visena(dot)com
> www.visena.com
> <https://www.visena.com>
>
>