如何为插入sql添加动态计数器

import pymysql

# 连接数据库
conn = pymysql.connect(host='localhost', user='root', password='password', database='mydb')
cursor = conn.cursor()

# 查询已有记录数量
cursor.execute("SELECT COUNT(*) FROM mytable")
row_count = cursor.fetchone()[0]

# 创建计数器变量
counter = row_count

# 生成插入SQL语句
sql = "INSERT INTO mytable (id, name) VALUES (%s, %s)"
values = (counter + 1, 'John Doe')

# 执行插入SQL语句
cursor.execute(sql, values)
conn.commit()

# 更新计数器变量
counter += 1

# 关闭数据库连接
cursor.close()
conn.close()

# 返回插入的行数
print("插入了", counter - row_count, "行数据")