Sort parent model by multiple child properties SQLAlchemy

Question

I'm using Python/Flask/SQLAlchemy. I have a class Contest which I want to sort by rating which is (tricky) the sum of its child (Side) properties. The formula for the rating is

leftside.score + len(leftside.votes) + rightside.score + len(leftside.votes)

Models:

class Contest(db.Model):
    leftside_id = db.Column(db.Text, db.ForeignKey('sides.id'))
    rightside_id = db.Column(db.Text, db.ForeignKey('sides.id'))

    leftside = db.relationship("Side", foreign_keys=[leftside_id])
    rightside = db.relationship("Side", foreign_keys=[rightside_id])

    rating = #??? leftside.score + len(leftside.votes) + rightside.score + len(leftside.votes)


class Side(db.Model):
    score = db.Column(db.Integer, default=0)
    votes = db.relationship('SideVote')

class SideVote(db.Model):
    side_id = db.Column(db.Text, db.ForeignKey('sides.id'))
    side = db.relationship('Side')

I can write a raw SQL, but it will return simple list, but I need SQLAlchemy query

SELECT *, (
    score
        + (SELECT COUNT(*) FROM sidevotes WHERE side_id = contests.leftside_id or side_id = contests.rightside_id)
    ) as Field
FROM contests, sides
WHERE contests.leftside_id = sides.id or contests.rightside_id = sides.id
ORDER BY Field DESC

So once again, I need to sort Contests by the formula written above, here I see 2 possible solutions:

• Either create some hybrid_property/column_property

• Or execute SQL and map it SQLAlchemy query so I can use this results