Flask-SQLAlchemy 原生 sql用法

ret = db.session.execute(" select TimeRecords.emp_id , Employee.emp_fname , Departs.depart_id , Departs.depart_name , TimeRecords.sign_time  "
                        " from  TimeRecords , Employee , Departs "
                        " where TimeRecords.emp_id = Employee.emp_id and Employee.depart_id = Departs.depart_id and "
                        " TimeRecords.emp_id ='{}'".format(emp_idd)
                        )

resu = list(ret)