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
27990	QuerySet.count() raises ValueError when QuerySet.union() is used	kapil garg	nobody	"When we get objects from a model and do union then the resulted QuerySet.count() raises ValueError due to the presence of Non-Numeric first Field.

Eg.


{{{
class SomeModel(models.Model):
    name = models.CharField(max_length=10, default='example')

>>> from bug.models import SomeModel
>>> e1 = SomeModel(name='current')
>>> e1.save()
>>> e2 = SomeModel()
>>> e2.save()
>>> qs1 = SomeModel.objects.filter(name__startswith='ex').only('name')
>>> qs2 = SomeModel.objects.filter(name__startswith='cu').only('name')
>>> qs = qs1.union(qs2)
>>> print(qs.count())
>>> #raises ValueError : invalid literal for int() with base 10
}}}

If the first field contained in queryset is numeric then this error is not raised.

Eg. remove .only() method above on both querysets and then .count() with return correct result."	Bug	closed	Database layer (models, ORM)	1.10	Normal	invalid			Unreviewed	0	0	0	0	0	0