On 19 Jun 2014, at 1:47, Jason Long <mailing.lists@xxxxxxxxxxxxxxxx> 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.
