id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
30093	queryset, union, order_by over an annotated field	Lorenzo Mele	nobody	"It seems that Django is kind of an overthinker when it comes to order by a field.

I need to make a union of two queries (queryset), the first one is ranked, the second one is not, in the final result I want a single queryset because it is going to be paginated.

I'll give you an example using the User model so you can try this at home.

  {{{#!python
from django.contrib.auth.models import User
from django.db.models import F, Value, IntegerField
from django.db.models.expressions import RawSQL

queryset = User.objects

a = queryset.filter(email__contains='a').annotate(rank=RawSQL(""rank() OVER (ORDER BY id desc)"", [], output_field=IntegerField()))
b = queryset.filter(email__contains='b').annotate(rank=Value(None, output_field=IntegerField()))

a.union(b).order_by(F('rank').desc(nulls_last=True))
# DatabaseError: ORDER BY term does not match any column in the result set.

a.order_by(F('rank').desc(nulls_last=True))
# this is OK

b.order_by(F('rank').desc(nulls_last=True))
# ProgrammingError: non-integer constant in ORDER BY
# LINE 1: ...ERE ""auth_user"".""email""::text LIKE '%b%' ORDER BY NULL DESC ...

a.union(b).order_by('rank')
# this is OK
  }}}

Is this a Django bug or am I doing something wrong?
"	Bug	new	Database layer (models, ORM)	1.11	Normal		queryset union annotate		Unreviewed	0	0	0	0	0	0