[sqlalchemy] Having trouble getting a subquery to return entities

[cbc]

Hi:

I'm having trouble getting a subquery to return entities.

class Question(Base):
        __tablename__ = 'question'
        question_id = Column(INTEGER(unsigned=True), primary_key=True)
        ...etc
        q_answers = relationship("Answer", backref="question")

class Answer(Base):
        __tablename__ = 'answer'
        answer_id = Column(INTEGER(unsigned=True), primary_key=True)
        user_id = Column(INTEGER(unsigned=True), ForeignKey('user.user_id'),
nullable=False)
        question_id = Column(INTEGER(unsigned=True),
ForeignKey('question.question_id'), nullable=False)
        ...etc

stmt = session.query(Answer).filter(Answer.user_id ==
user_id).subquery()
answers = aliased(Answer, stmt)
query = session.query(Question, answers)\
        .outerjoin(answers, Question.q_answers)\
        .filter(Question.question_group_id == question_group_id)
questions = query.all()

This generates MySQL that returns all desired columns and returns NULL
if question has not yet been answered by the specified user. Groovy so
far.

I was expecting tuples in the list of questions (Answer, Question),
but the first element is always None. e.g.

>>> dir(questions[0])
[None, 'Question', ... etc

So while I'm expecting the subquery results to be understood as
entities (Answer), this isn't happening. But I cannot figure out why.

Where have I failed?

Thanks!

-C

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