Aren't you missing a ForeignKey relationship to tell which LlamaHerd a Llama belongs to?
Then you would use the reverse relation manager in LlamaHerd to build up your annotation. On Tue, Apr 1, 2014 at 5:52 PM, Justin Holmes <[email protected]>wrote: > I have come across this problem in several Django projects, but only just > now worked it out in my head enough to make it a cognizable question. > > I have also posted it on StackOverflow, here: > http://stackoverflow.com/questions/22797497/using-the-django-orm-to-order-by-a-value-in-a-distinct-related-item > > > Consider this example: > > class LlamaHerd(models.Model): > shepherd = ForeignKey(User) > > class Llama(models.Model): > size = FloatField() > dob = FloatField > > How can I now make a query to get LlamaHerd objects, sorted by the date of > birth of their largest llama? > > It almost feels like I might be able to use annotate: > > LlamaHerd.annotate(largest_llama=Max('llama__size')).order_by('largest_llama__dob') > > ...but the annotate here creates fields with float values, not with the > model instances. > > > -- > Justin Holmes > Chief Chocobo Breeder, slashRoot > > slashRoot: Coffee House and Tech Dojo > New Paltz, NY 12561 > 845.633.8330 > > -- > You received this message because you are subscribed to the Google Groups > "Django users" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/django-users. > To view this discussion on the web visit > https://groups.google.com/d/msgid/django-users/CAMGywB6gkBvhFs%2BP2PrtDah24VDCko8QK-1UCnSGugz_ts1v8g%40mail.gmail.com<https://groups.google.com/d/msgid/django-users/CAMGywB6gkBvhFs%2BP2PrtDah24VDCko8QK-1UCnSGugz_ts1v8g%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "Django users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/django-users. To view this discussion on the web visit https://groups.google.com/d/msgid/django-users/CAB%2BAj0srKNzRs%3DzbsPm%2BobxLNFCcjRccGSVeYykF1PSnJc-ydQ%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
