models.py

class Supplier(db.Model):
    """A supplier of consignment items."""
    __tablename__ = 'consignment_suppliers'

    id = db.Column(db.Integer, primary_key=True)
    supplier_name = db.Column(db.String(200),
                              unique=True,
                              info={'label': 'Business name',
                                    'filters': [lambda x: x or None]})
    person_id = db.Column(db.Integer, db.ForeignKey('person.id'))
    person = db.relationship('Person', uselist=False)

    products = db.relationship('Product',
                               backref=db.backref('supplier', lazy='joined'),
                               lazy='dynamic')

    @property
    def name(self):
        """Harmonizes suppliers with business names vs personal names."""
        if self.supplier_name:
            return self.supplier_name
        return self.person.name

# Example call:
items = Product.query.join(Supplier).join(Person).order_by(asc(func.coalesce(Supplier.supplier_name, Person.name))).all()

output.sql

sqlalchemy.exc.OperationalError: (sqlite3.OperationalError) no such column: consignment_suppliers.supplier_name [SQL: 'SELECT consignment_products.id AS consignment_products_id, consignment_products.supplier_id AS consignment_products_supplier_id, consignment_products.description AS consignment_products_description, consignment_products.quantity AS consignment_products_quantity, consignment_products.created AS consignment_products_created, consignment_products.updated AS consignment_products_updated, consignment_products.price AS consignment_products_price, consignment_products.rate AS consignment_products_rate, consignment_suppliers_1.id AS consignment_suppliers_1_id, consignment_suppliers_1.supplier_name AS consignment_suppliers_1_supplier_name, consignment_suppliers_1.person_id AS consignment_suppliers_1_person_id, consignment_suppliers_1.created AS consignment_suppliers_1_created, consignment_suppliers_1.updated AS consignment_suppliers_1_updated, consignment_suppliers_1.active AS consignment_suppliers_1_active, consignment_suppliers_1.hst AS consignment_suppliers_1_hst, consignment_suppliers_1.rate AS consignment_suppliers_1_rate, consignment_suppliers_1.notes AS consignment_suppliers_1_notes, consignment_suppliers_1.earned AS consignment_suppliers_1_earned \nFROM consignment_products LEFT OUTER JOIN consignment_suppliers AS consignment_suppliers_1 ON consignment_suppliers_1.id = consignment_products.supplier_id ORDER BY coalesce(consignment_suppliers.supplier_name, person.name) ASC, lower(consignment_products.description) ASC\n LIMIT ? OFFSET ?'] [parameters: (50, 0)]

raw.sql

SELECT consignment_products.*, 
	COALESCE(consignment_suppliers.supplier_name, person.name) AS supplier_name
FROM consignment_products, person JOIN consignment_suppliers ON consignment_suppliers.id == consignment_products.supplier_id
WHERE person.id == consignment_suppliers.person_id;

For reference of any people led here by a search:

Line 32 is an incorrect call—my view has two cases, one where we're looking a specific supplier and one where we're looking at all products from all suppliers. I needed to use a join. When I did this, everything works without a hybrid property.

The most recent revision of the gist has been updated to show the working code.