Re: Slow query: Select all buildings that have >1 pharmacies and >1 schools within 1000m

On Tue, Aug 7, 2012 at 5:07 PM, Stefan Keller <sfkeller(at)gmail(dot)com> wrote:
> Hi Craig
>
> Clever proposal!
> I slightly tried to adapt it to the hstore involved.
> Now I'm having a weird problem that PG says that "relation 'p' does not exist".
> Why does PG recognize table b in the subquery but not table p?
> Any ideas?

I don't think it does recognize b, either. It just fell over on p
before it had a chance to fall over on b.

I think you have to use WITH if you want to reference the same
subquery in multiple FROMs.

Another approach would be to add explicit conditions for there being
at least 1 school and 1 pharmacy within distance. There can't be >1
unless there is >=1, but the join possibilities for >=1 (i.e. "where
exists" rather than "where (select count(*)...)>1" ) are much more
attractive than the ones for >1.

Cheers,

Jeff