SqlAlchemy外部联接仅返回一个表

Question

So when I run select * from table1 t1 left outer join table2 t2 on t1.id = t2.id; in sqlite3 terminal

I get the data back as I want and would expect.

However, when I run this in SqlAlchemy TableOneModel.query.outerjoin(TableTwoModel,TableOneModel.id == TableTwoModel.id)

I only get table1 information back. I don't even get empty columns from table2 . Am I missing something silly?

Answer 1

You're probably using Flask-SQLAlchemy, which provides the query property as a shortcut for selecting model entities. Your query is equivalent to

db.session.query(TableOneModel).\
    join(TableTwoModel,TableOneModel.id == TableTwoModel.id)

Either explicitly query for both entities:

db.session.query(TableOneModel, TableTwoModel).\
    join(TableTwoModel,TableOneModel.id == TableTwoModel.id)

or add the entity to your original:

TableOneModel.query.\
    join(TableTwoModel,TableOneModel.id == TableTwoModel.id).\
    add_entity(TableTwoModel)