在MySQL和python中如何使用字段名而不是字段索引来访问字段

SELECT username, email FROM users;

import pymysql

# 连接到MySQL数据库
conn = pymysql.connect(host='localhost', user='username', password='password', db='database_name')

# 创建游标对象
cursor = conn.cursor()

# 执行查询语句
cursor.execute("SELECT username, email FROM users")

# 获取查询结果
results = cursor.fetchall()

# 遍历结果并打印字段值
for row in results:
    username = row[0]  # 使用字段索引访问字段值
    email = row[1]
    print("Username: {}, Email: {}".format(username, email))

# 关闭游标和数据库连接
cursor.close()
conn.close()