Sqlalchemy from_statement() cannot locate column

Question

I am following the sqlalchemy tutorial in http://docs.sqlalchemy.org/en/rel_0_9/orm/tutorial.html

Nevertheless, instead of using a SQLite backend, I am using MySQL. The problem is that when I try to execute a literal MySQL statement to select a column from the users table, such as

SELECT name from users;

it will fail with

NoSuchColumnError: "Could not locate column in row for column 'users.id'"

whereas doing a

SELECT * FROM users

will work just fine. Am I missing anything?

The Users class is defined as :

class User(Base):
    __tablename__ = 'users'
    id = Column(Integer, primary_key=True)
    name = Column(String(50))
    fullname = Column(String(50))
    password = Column(String(50))
    def __repr__(self):
        return "<User(name='%s', fullname='%s', password='%s')>" % (self.name, self.fullname, self.password)

The session is defined as:

Session = sessionmaker(bind=engine)
session = Session()

And I am trying to do

session.query(Users).from_statement('SELECT name from users')

By the way, this statement works fine when run on a MySQL client. Am I missing something or is it a bug?

Answer 1

I answer myself in case someone has the same problem. The syntax of

session.query(Users).from_statement('SELECT name from users')

is wrong. It should be

session.query('name').from_statement('SELECT name from users')

The list of columns should be in the call to query().