Ah, yes, that makes sense. Thank you! On Thu, Mar 1, 2012 at 11:39 AM, Claudio Freire <klaussfre...@gmail.com>wrote:
> On Thu, Mar 1, 2012 at 4:35 PM, Alessandro Gagliardi > <alessan...@path.com> wrote: > > Interesting solution. If I'm not mistaken, this does solve the problem of > > having two entries for the same user at the exact same time (which > violates > > my pk constraint) but it does so by leaving both of them out (since > there is > > no au1.hr_timestamp > au2.hr_timestamp in that case). Is that right? > > Yes, but it would have to be same *exact* time (not same hour). > > You can use more fields to desambiguate too, ie: > > au1.hr_timestamp > au2.hr_timestamp or (au1.hr_timestamp == > au2.hr_timestamp and au1.some_other_field > au2.some_other_field) > > If you have a sequential id to use in desambiguation, it would be best. >
