Django ORM: Chaining aggregated querysets into one

Question

Can I chain these two querysets into one?

qs1 = OrderTicket.objects.filter(date__gt=datetime.date(2009, 1, 1), date__lt=datetime.date(2009, 1, 30)).values('order_type').annotate(value_1 = Sum('gbp_value')).order_by('order_type'),
qs2 = OrderTicket.objects.filter(date__gt=datetime.date(2009, 2, 1), date__lt=datetime.date(2009, 2, 30)).values('order_type').annotate(value_2 = Sum('gbp_value')).order_by('order_type'),

All I want is the value_1 and value_2 columns. Q objects are not what I need. Maybe the ORM does not support this.

Answer 1

I would suggest using Q objects to replace your filter for date__gt and date__lt

Example (not tested):

qs1 = OrderTicket.objects
    .filter(  Q(date__gt=datetime.date(2009, 1, 1), date__lt=datetime.date(2009, 1, 30)) 
      | Q(date__gt=datetime.date(2009, 2, 1), date__lt=datetime.date(2009, 2, 30))
        )
    .values('order_type').annotate(value_1 = Sum('gbp_value')).order_by('order_type')

This should return both the dates you are looking for.

Answer 2

You can combine querysets using the | and & operators:

# You can combine queries with & and |.
>>> s1 = Article.objects.filter(id__exact=1)
>>> s2 = Article.objects.filter(id__exact=2)
>>> s1 | s2
[<Article: Area woman programs in Python>, <Article: Second article>]
>>> s1 & s2
[]

Source http://www.djangoproject.com/documentation/models/basic/