选择每个类别中具有最大时间戳的行

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

Base = declarative_base()

class MyClass(Base):
    __tablename__ = 'my_table'
    id = Column(Integer, primary_key=True)
    name = Column(String)
    timestamp = Column(DateTime)

engine = create_engine('sqlite:///my_database.db')
Base.metadata.create_all(engine)

Session = sessionmaker(bind=engine)
session = Session()

# 查询具有最大时间戳的行
max_timestamp_row = session.query(MyClass).order_by(MyClass.timestamp.desc()).first()

print(max_timestamp_row.name, max_timestamp_row.timestamp)