sqlalchemy.exc.ProgrammingError 烧瓶

Question

我有一个带有 postgresql 的 flask 应用程序，我想根据用户最好的朋友的名字对用户进行排序。为了解释它在 bestfriend 中具有一对一关系的数据库，我使用 flask-migrate 并且 Alembic.But 得到了这个错误，如果你能告诉我我该如何解决它以及问题出在哪里？

error

sqlalchemy.exc.ProgrammingError

ProgrammingError: (ProgrammingError) column "users_1.name" must appear in the GROUP BY clause or be used in an aggregate function LINE 2: FROM users JOIN (SELECT users.name AS name, users_1.name AS

... ^ 'SELECT users.id AS users_id, users.name AS users_name, users.age AS users_age, users.email AS users_email, users.bestfriend_id AS users_bestfriend_id \nFROM users JOIN (SELECT users.name AS name, users_1.name AS fn \nFROM users JOIN users AS users_1 ON users_1.id = users.bestfriend_id GROUP BY users.name) AS anon_1 ON anon_1.name = users.name ORDER BY anon_1.fn ASC \n LIMIT %(param_1)s OFFSET %(param_2)s' {'param_1': 2, 'param_2': 0}

model.py:

friends = db.Table('friends',
db.Column('user_id', db.Integer, db.ForeignKey('users.id')),
db.Column('friend_id', db.Integer, db.ForeignKey('users.id'))
)

class Users(db.Model):
   id = db.Column(db.Integer, primary_key = True)
   name = db.Column(db.String(50), index=True)
   age= db.Column(db.Integer )
   email = db.Column(db.String(50),index=True, unique= True)
   bestfriend_id = db.Column(db.Integer, db.ForeignKey('users.id', ondelete ='SET NULL'), nullable=True)
   

   is_bestfriend = db.relationship( 'Users', uselist=False, remote_side=[id], post_update=True)

view.py

#condition to sort base on bestfriend name                  
    elif request.args.get('sort') == 'bf':
           sortBy = 'bf'
           friend = db.aliased(Users)
           sub = db.session.query(
                   Users.name, friend.name.label('fn')).\
                   join(friend, Users.is_bestfriend).group_by(Users.name).subquery()

           monkey = Users.query.join(sub, sub.c.name == Users.name).\
                        order_by(sub.c.fn.asc()).paginate(page, MONKEYS_PAGE, False)

Answer 1

您忘记将 friend.name.label('fn') 添加到群组

join(friend, Users.is_bestfriend).group_by(Users.name).group_by('fn').subquery()

sqlalchemy.exc.ProgrammingError 烧瓶

sqlalchemy.exc.ProgrammingError for flask

python

database

postgresql

sqlalchemy

flask