如何在SQLAlchemy中连接来自不同数据库的两个表？

from sqlalchemy import create_engine, Column, Integer, String
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker

# 创建数据库引擎和连接
engine1 = create_engine('mysql://username:password@host:port/database1')
engine2 = create_engine('postgresql://username:password@host:port/database2')

# 创建基类
Base1 = declarative_base(bind=engine1)
Base2 = declarative_base(bind=engine2)

# 定义映射模型
class Table1(Base1):
    __tablename__ = 'table1'
    id = Column(Integer, primary_key=True)
    name = Column(String)

class Table2(Base2):
    __tablename__ = 'table2'
    id = Column(Integer, primary_key=True)
    value = Column(String)

# 创建会话工厂
Session1 = sessionmaker(bind=engine1)
Session2 = sessionmaker(bind=engine2)

# 创建会话对象
session1 = Session1()
session2 = Session2()

# 连接两个表
query = session1.query(Table1, Table2).join(Table2, Table1.id == Table2.id)

# 添加其他查询条件
query = query.filter(Table1.name == 'example')

# 执行查询
result = query.all()