如何在同一函数中查询SELECT和UPDATE

import MySQLdb

def query_and_update():
    # 连接数据库
    conn = MySQLdb.connect(host='localhost', port=3306, user='username', passwd='password', db='database')
    cursor = conn.cursor()

    try:
        # 执行SELECT查询
        cursor.execute("SELECT * FROM table_name WHERE condition")
        results = cursor.fetchall()

        # 处理查询结果
        for row in results:
            # 处理每一行数据

        # 执行UPDATE操作
        cursor.execute("UPDATE table_name SET column1=value1 WHERE condition")

        # 提交事务
        conn.commit()

    except Exception as e:
        # 发生错误时回滚事务
        conn.rollback()
        print("Error: ", e)

    finally:
        # 关闭数据库连接
        cursor.close()
        conn.close()