Question

我有一个带有postgresql的烧瓶应用程序，我想根据他们最好的朋友名称对用户进行排序。为了解释数据库，它在bestfriend中有一对一的关系，我使用flask-migrate和Alembic.But得到了这个错误，但是如果你能告诉我如何解决它，问题出在哪里？

错误

sqlalchemy.exc.ProgrammingError

ProgrammingError :( ProgrammingError）列＆＃34; users_1.name＆＃34;必须出现   在GROUP BY子句中或在聚合函数LINE 2中使用：   FROM users JOIN（SELECT users.name AS name，users_1.name AS

... ^＆＃39; 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用户加入（选择   users.name AS名称，users_1.name AS fn \ nFROM用户JOIN用户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＆＃39; {＆＃39; param_1＆＃39;：2，＆＃39; param_2＆＃39;：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

您忘了通过

将friend.name.label（'fn'）添加到群组中

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

烧瓶的sqlalchemy.exc.ProgrammingError

1 个答案: