Re: Multiple-Table-Spanning Joins with ORs in WHERE Clause

On Thu, Sep 29, 2016 at 11:48 AM, Sven R. Kunze <srkunze(at)mail(dot)de> wrote:

> On 29.09.2016 20:03, Jeff Janes wrote:
>
> Perhaps some future version of PostgreSQL could do so, but my gut feeling
> is that that is not very likely. It would take a lot of work, would risk
> breaking or slowing down other things, and is probably too much of a niche
> issue to attract a lot of interest.
>
>
> I don't hope so; in business and reports/stats applications there is a lot
> of room for this.
>
> Why do you think that OR-ing several tables is a niche issue? I can at
> least name 3 different projects (from 3 different domains) where combining
> 3 or more tables with OR is relevant and should be reasonably fast.
>

Well, I don't recall seeing this issue on this list before (or a few other
forums I read) while I see several other issues over and over again. So
that is why I think it is a niche issue. Perhaps I've have seen it before
and just forgotten, or have not recognized it as being the same issue each
time.

> This multitude of solution also shows that applications developers might
> be overwhelmed by choosing the most appropriate AND most long-lasting one.
> Because what I take from the discussion is that a UNION might be
> appropriate right now but that could change in the future even for the very
> same use-case at hand.
>

I'm not sure what would cause it to change. Do you mean if you suddenly
start selecting a much larger portion of the table? I don't know that the
union would be particularly bad in that case, either.

I'm not saying it wouldn't be nice to fix it. I just don't think it is
particularly likely to happen soon. I could be wrong (especially if you
can write the code to make it happen).

Cheers,

Jeff