Trouble with sqlalchemy join query - get the next date from child - sqlalchemy

Question

Using the example below, i'm trying to make a single query that will get my list of offices, and pull the next upcoming visit from the child table.
class Office(db.Model):
id = db.Column(db.Integer, primary_key=True)
office_name = db.Column(db.String(100))
visits = db.relationship('Visit', backref='office', lazy='select', order_by='desc(Visit.visit_date)')
class Visit(db.Model):
id = db.Column(db.Integer, primary_key=True)
visit_date = db.Column(db.Date)
office_id = db.Column(db.Integer, db.ForeignKey('office.id'))
I've been able to create a query in raw SQL that will return what i need:
SELECT * FROM office
LEFT OUTER JOIN ( SELECT office_id, visit_date FROM visit WHERE visit_date >= date('now')
GROUP BY office_id )
AS next_vis ON id = next_vis.office_id
But i haven't been able to convert the above in SQLAlchemy.
Closest i've got to is this:
next_vis = db.session.query(Visit.office_id, Visit.visit_date).filter(
Visit.visit_date >= datetime.utcnow().date()).order_by(
Visit.visit_date.asc()).group_by(Visit.office_id).subquery()
offices = db.session.query(Office, next_vis.c.visit_date).outerjoin(
next_vis, Office.id == next_vis.c.office_id).order_by(
Office.office_name.asc())
But the only problem is it returns a tuple of (office, date) but ideally i want it returned as a single object. Is that not possible?
Thanks!

Answer 1

If anyone is interested i went about this a slightly different way.
I switched from a join query to adding a column property in my Office model:
class Office(db.Model):
id = db.Column(db.Integer, primary_key=True)
office_name = db.Column(db.String(100))
visits = db.relationship('Visit', backref='office', lazy='select',
order_by='desc(Visit.visit_date)')
next_vis = column_property(
select([Visit.visit_date]).where(
and_(Visit.office_id == id, Visit.visit_date >= db.func.current_date())).order_by(
Visit.visit_date.asc()).correlate_except(Visit))
Now when i do Office.query.all() i can do:
for i in Office.query.all():
print(i.next_vis)
If i've overlooked anything please let me know!
Thanks,