python - Query returns different data when using MySQL versus SQLite -

when query following model sqlalchemy, don't expected result.

class user(db.model):     __tablename__ = 'users'     id = db.column(db.integer, primary_key=true)     username = db.column(db.string(64), unique=true)      def __repr__(self):         return '<user %r>' % self.username 

i created mysql table directly, committe data:

mysql> create table "users" (id integer, username varchar(64));  mysql> select * users;   +------+-------------+---------+   | id   | username    | role_id |   +------+-------------+---------+   | null | yzxu        | null    |    | null | after       | null    |   +------+-------------+---------+   

when using mysql, sqlalchemy query returns none.

>>> user.query.filter_by(username='after').all() [none] 

when using sqlite, correct username returned.

>>> db.create_all() >>> db.session.add(user(username='after')) >>> db.session.commit() >>> user.query.filter_by(username='after').all() [<user u'after'>] 

the mysql table created manually me without sqlalchemy. missing primary key set on id.