如何使用psycopg2指定列名

import psycopg2

# 连接到PostgreSQL数据库
conn = psycopg2.connect(database="mydb", user="myuser", password="mypassword", host="localhost", port="5432")

# 创建一个数据库游标
cur = conn.cursor()

# 执行SQL查询语句并获取结果
cur.execute("SELECT column1 AS alias1, column2 AS alias2 FROM mytable")

# 通过fetchall()方法获取所有结果行
rows = cur.fetchall()

# 遍历结果并打印指定列名的值
for row in rows:
    print("Alias1:", row[0])
    print("Alias2:", row[1])

# 关闭游标和数据库连接
cur.close()
conn.close()