On 19 Jun 2014, at 1:47, Jason Long <mailing.li...@octgsoftware.com> wrote:

> I have a large table of access logs to an application.  
> 
> I want is to find all rows that overlap startdate and enddate with any
> other rows.
> 
> The query below seems to work, but does not finish unless I specify a
> single id.  
> 
> select distinct a1.id
> from t_access a1, 
>        t_access a2 
> where tstzrange(a1.startdate, a1.enddate) && 
>      tstzrange(a2.startdate, a2.enddate) 

You’re comparing overlapping records twice there; you compare all records in a1 
to all records in a2. You’ll want to skip the records that you already compared.

Alban Hertroys
--
If you can't see the forest for the trees,
cut the trees and you'll find there is no forest.



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