python - Flask SQLAlchemy order_by relationship -

i'm working flask application have largegroupattendance model references model called attendee. i'm trying request of largegroupattendance objects match criteria, i'm trying sort them column of attendee model - possible? here 2 models below:

""" attendeee class """ class attendee(base):     __tablename__ = 'attendee'      id = column(integer, primary_key=true)     first_name = column(string(200))     last_name = column(string(200))     year = column(string(200))     email = column(string(100), unique=true)     dorm = column(string(100))      def __init__(self, first_name, last_name, year, email, dorm):         self.first_name = first_name         self.last_name = last_name         self.year = year         self.email = email         self.dorm = dorm      def __repr__(self):         return '<attendee %r>' % self.first_name  """ large group attendance class """ class largegroupattendance(base):     __tablename__ = 'large_group_attendance'      id = column(integer, primary_key=true)     first_time = column(integer)      large_group_id = column(integer, foreignkey('large_group.id'))     large_group = relationship("largegroup", backref=backref('large_group_attendance', order_by=id))      attendee_id = column(integer, foreignkey('attendee.id'))     attendee = relationship("attendee", backref=backref('large_group_attendance', order_by=id)) 

do need add attendee class make possible? , here's query i've tried before, it's had no output (no errors either..). going wrong?

    attendance_records = db.session.query(largegroupattendance).filter_by(large_group_id=event_id).order_by(desc(largegroupattendance.attendee.first_name))  

i think need add join query, this:

.join(largegroupattendance.attendee) 

so final query this:

attendance_records = (db.session.query(largegroupattendance).     filter_by(large_group_id = event_id).     join(attendee, largegroupattendance.attendee).     order_by(desc(attendee.first_name))     ) 

see sqlalchemy: how order query results (order_by) on relationship's field? more detailed explanation