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
34229	"""no such column"" when combining FilteredRelation and multi-table inheritance models"	Javier Ayres	Turonbek Kuzibaev	"I have found that a certain queryset that combines multi-table inheritance models, FilteredRelation, and aggregation, can result in a ""no such column"" database error. 

The following `models.py` and `tests.py` modules can be placed in the app of a newly created Django project to reproduce the bug. I've successfully reproduced it with Django 3.2.4 (using PostgreSQL) and 4.1.4 (using sqlite3). The tests module includes two tests which are pretty similar, however one of them fails because of this bug, the full stacktrace being:
{{{
Traceback (most recent call last):
  File ""/tmp/env/lib/python3.10/site-packages/django/db/backends/utils.py"", line 89, in _execute
    return self.cursor.execute(sql, params)
  File ""/tmp/env/lib/python3.10/site-packages/django/db/backends/sqlite3/base.py"", line 357, in execute
    return Database.Cursor.execute(self, query, params)
sqlite3.OperationalError: no such column: myapp_user.superuser

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File ""/tmp/dec1389/myapp/tests.py"", line 34, in test_fails
    print(
  File ""/tmp/env/lib/python3.10/site-packages/django/db/models/query.py"", line 370, in __repr__
    data = list(self[: REPR_OUTPUT_SIZE + 1])
  File ""/tmp/env/lib/python3.10/site-packages/django/db/models/query.py"", line 394, in __iter__
    self._fetch_all()
  File ""/tmp/env/lib/python3.10/site-packages/django/db/models/query.py"", line 1867, in _fetch_all
    self._result_cache = list(self._iterable_class(self))
  File ""/tmp/env/lib/python3.10/site-packages/django/db/models/query.py"", line 87, in __iter__
    results = compiler.execute_sql(
  File ""/tmp/env/lib/python3.10/site-packages/django/db/models/sql/compiler.py"", line 1398, in execute_sql
    cursor.execute(sql, params)
  File ""/tmp/env/lib/python3.10/site-packages/django/db/backends/utils.py"", line 67, in execute
    return self._execute_with_wrappers(
  File ""/tmp/env/lib/python3.10/site-packages/django/db/backends/utils.py"", line 80, in _execute_with_wrappers
    return executor(sql, params, many, context)
  File ""/tmp/env/lib/python3.10/site-packages/django/db/backends/utils.py"", line 84, in _execute
    with self.db.wrap_database_errors:
  File ""/tmp/env/lib/python3.10/site-packages/django/db/utils.py"", line 91, in __exit__
    raise dj_exc_value.with_traceback(traceback) from exc_value
  File ""/tmp/env/lib/python3.10/site-packages/django/db/backends/utils.py"", line 89, in _execute
    return self.cursor.execute(sql, params)
  File ""/tmp/env/lib/python3.10/site-packages/django/db/backends/sqlite3/base.py"", line 357, in execute
    return Database.Cursor.execute(self, query, params)
django.db.utils.OperationalError: no such column: myapp_user.superuser
}}}

=== models.py:
{{{
from django.db import models

class School(models.Model):
    name = models.CharField(max_length=100)


class User(models.Model):
    superuser = models.BooleanField(default=True)


class Student(User):
    superstudent = models.BooleanField(default=True)
    school = models.ForeignKey(School, on_delete=models.CASCADE)
}}}

=== tests.py
{{{
from django.test import TestCase
from django.db.models import Q, FilteredRelation, Count
from .models import School, Student


class FilteredRelationBugTestCase(TestCase):

    @classmethod
    def setUpClass(cls):
        super().setUpClass()
        p = School.objects.create(name='p1')
        Student.objects.create(school=p, superuser=False, superstudent=False)
        Student.objects.create(school=p, superuser=False, superstudent=True)
        Student.objects.create(school=p, superuser=True, superstudent=False)
        Student.objects.create(school=p, superuser=True, superstudent=True)

    def test_works(self):
        print(
            School.objects.annotate(
                superstudents=FilteredRelation(
                    'student',
                    condition=Q(
                        student__superstudent=True,
                    ),
                ),
                superuser_count=Count(
                    'superstudents',
                    filter=Q(superstudents__superuser=True)
                ),
            ).all()
        )

    def test_fails(self):
        print(
            School.objects.annotate(
                superusers=FilteredRelation(
                    'student',
                    condition=Q(
                        student__superuser=True,
                    ),
                ),
                superstudents_count=Count(
                    'superusers',
                    filter=Q(superusers__superstudent=True)
                ),
            ).all()
        )
}}}"	Bug	assigned	Database layer (models, ORM)	4.1	Normal		filteredrelation such column		Accepted	0	0	0	0	0	0