Call annotate after union will raise error, why, how can I solve it?

[Louie Feng]

Call annotate after union will raise error, why, how can I solve it?

For example:

cards = card10.union(SCPSimcard.objects.filter(pk=7))

cards.annotate(n=F('id'))

the follow is traceback info:

Traceback (most recent call last):

  File "<console>", line 1, in <module>

  File "C:\Users\hasee\Envs\tb_simcard\lib\site-packages\django\db\models\query.py", line 250, in __repr__

    data = list(self[:REPR_OUTPUT_SIZE + 1])

  File "C:\Users\hasee\Envs\tb_simcard\lib\site-packages\django\db\models\query.py", line 274, in __iter__

    self._fetch_all()

  File "C:\Users\hasee\Envs\tb_simcard\lib\site-packages\django\db\models\query.py", line 1242, in _fetch_all

    self._result_cache = list(self._iterable_class(self))

  File "C:\Users\hasee\Envs\tb_simcard\lib\site-packages\django\db\models\query.py", line 78, in __iter__

    setattr(obj, attr_name, row[col_pos])

IndexError: list index out of range