如果一条查询语句是以filter结尾，则返回结果对象的__str__方法中都是SQL语句：
result = session.query(Teachers).filter() print(result) # SELECT teachers.id AS teachers_id, teachers.name AS teachers_name # FROM teachers如果是all结尾，返回的就是一个列表，first结尾也是一个列表：
result = session.query(Teachers).all() print(result) # [<models.Teachers object at 0x00000178EB0B5550>, <models.Teachers object at 0x00000178EB0B5518>, <models.Teachers object at 0x00000178EB0B5048>] 执行SQL语句执行原生SQL：
from sqlalchemy.orm import scoped_session from sqlalchemy.orm import sessionmaker # 导入引擎，模型表等 from models import * # 通过Session绑定引擎和数据库建立关系 Session = sessionmaker(bind=engine) # 创建链接池，使用session即可为当前线程拿出一个链接对象。内部采用threading.local进行隔离 session = scoped_session(Session) cursor = session.execute(r"select * from students where id <= (:num)",params={"num":2}) print(cursor.fetchall()) # 提交 session.commit() # 关闭链接 session.close()