On Thu, Sep 29, 2016 at 11:48 AM, Sven R. Kunze <srkunze@mail.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).
