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
28838	annotations + base_manager_name + instance.save() raises exception	James Addison	shangdahao	"With a models.py like:
{{{#!python
class ItemManager(models.Manager):
    def get_queryset(self):
        return super().get_queryset().annotate(
            rating_avg=models.Avg('review__rating')
        )


class Item(models.Model):
    name = models.CharField(max_length=10, default='')

    objects = ItemManager()

    class Meta:
        base_manager_name = 'objects'


class Review(models.Model):
    item = models.ForeignKey(Item)
    rating = models.PositiveSmallIntegerField(default=0)
}}}

If an `Item` instance is modified and `item.save()` is called like this:
{{{
    item = Item.objects.first()
    item.name = 'abc'
    item.save()
}}}
It will raise this exception:
{{{
Traceback (most recent call last):
  File ""/home/myuser/django_annotations_bug/the_bug/tests.py"", line 9, in test_bug_will_be_triggered
    item.save()
  File ""/home/myuser/.virtualenvs/django_annotations_bug/lib/python3.6/site-packages/django/db/models/base.py"", line 808, in save
    force_update=force_update, update_fields=update_fields)
  File ""/home/myuser/.virtualenvs/django_annotations_bug/lib/python3.6/site-packages/django/db/models/base.py"", line 838, in save_base
    updated = self._save_table(raw, cls, force_insert, force_update, using, update_fields)
  File ""/home/myuser/.virtualenvs/django_annotations_bug/lib/python3.6/site-packages/django/db/models/base.py"", line 905, in _save_table
    forced_update)
  File ""/home/myuser/.virtualenvs/django_annotations_bug/lib/python3.6/site-packages/django/db/models/base.py"", line 955, in _do_update
    return filtered._update(values) > 0
  File ""/home/myuser/.virtualenvs/django_annotations_bug/lib/python3.6/site-packages/django/db/models/query.py"", line 664, in _update
    return query.get_compiler(self.db).execute_sql(CURSOR)
  File ""/home/myuser/.virtualenvs/django_annotations_bug/lib/python3.6/site-packages/django/db/models/sql/compiler.py"", line 1199, in execute_sql
    cursor = super(SQLUpdateCompiler, self).execute_sql(result_type)
  File ""/home/myuser/.virtualenvs/django_annotations_bug/lib/python3.6/site-packages/django/db/models/sql/compiler.py"", line 894, in execute_sql
    raise original_exception
  File ""/home/myuser/.virtualenvs/django_annotations_bug/lib/python3.6/site-packages/django/db/models/sql/compiler.py"", line 884, in execute_sql
    cursor.execute(sql, params)
  File ""/home/myuser/.virtualenvs/django_annotations_bug/lib/python3.6/site-packages/django/db/backends/utils.py"", line 65, in execute
    return self.cursor.execute(sql, params)
  File ""/home/myuser/.virtualenvs/django_annotations_bug/lib/python3.6/site-packages/django/db/utils.py"", line 94, in __exit__
    six.reraise(dj_exc_type, dj_exc_value, traceback)
  File ""/home/myuser/.virtualenvs/django_annotations_bug/lib/python3.6/site-packages/django/utils/six.py"", line 685, in reraise
    raise value.with_traceback(tb)
  File ""/home/myuser/.virtualenvs/django_annotations_bug/lib/python3.6/site-packages/django/db/backends/utils.py"", line 65, in execute
    return self.cursor.execute(sql, params)
  File ""/home/myuser/.virtualenvs/django_annotations_bug/lib/python3.6/site-packages/django/db/backends/sqlite3/base.py"", line 328, in execute
    return Database.Cursor.execute(self, query, params)
django.db.utils.OperationalError: sub-select returns 2 columns - expected 1
}}}

I have attached a simple sample project that reproduces this error. To set it up:
{{{
tar xzvf bug.tgz
cd django_annotations_bug
mkvirtualenv -ppython3 buggy_mcbugface
pip install -r requirements.txt
./manage.py test
}}}

Related to #19513, #28374, #26539 - this those are related to `.update()` calls, mostly. This example does not use the annotation in the save/updating of the item, so is different I think."	Bug	closed	Database layer (models, ORM)	1.11	Normal	fixed			Ready for checkin	1	0	0	0	0	0