拆分group by，sqlalchemy flask中的计数值

from flask import Flask
from flask_sqlalchemy import SQLAlchemy

app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///example.db'
db = SQLAlchemy(app)

class User(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(50))
    age = db.Column(db.Integer)
    city = db.Column(db.String(50))

@app.route('/user-count-by-city')
def user_count_by_city():
    result = db.session.query(User.city, db.func.count(User.id)).group_by(User.city).all()
    return {'result': [(city, count) for city, count in result]}

# 错误的示例
result = db.session.query(User.name, db.func.count(User.id)).group_by(User.city).all()

# 正确的示例
result = db.session.query(User.city, db.func.count(User.id)).group_by(User.city).all()

result = db.session.query(User.city, db.func.count(User.id)).group_by(User.city).order_by(db.desc(db.func.count(User.id))).all()