我正在为现有的mysql数据库构建一个新的python3接口。名为“tickets”的表可能包含或不包含特定成员的行。如果票号存在的话，我就去拿，如果没有，我就去做别的事情。我的代码如下所示：

import mysql.connector
config = {
  'user': 'XXXXXXXXXXXXX',
  'password': 'XXXXXXXXXXXXX',
  'host': 'XXXXXXXXXXXXX',
  'database': 'XXXXXXXXXXXXX',
  'raise_on_warnings': True
}
membernum = 9
db = mysql.connector.connect(**config)
if db.is_connected():
    cursor = db.cursor()
    query = "SELECT ticketnum FROM Tickets WHERE membernum={} limit 1".format(membernum)
    cursor.execute(query)
    if cursor.rowcount == 0:
        print("No results")
    else:
        result = cursor.fetchone()
        ticketnum = result[0]
        print(ticketnum)
    cursor.close
    db.close
else:
    print("Connection error")

如果有一个与该成员匹配的记录，那么它工作得很好。如果不是，则生成：

Traceback (most recent call last):
  File "/Users/Gary/IPPS/samplecode.py", line 22, in <module>
    ticketnum = result[0]
TypeError: 'NoneType' object is not subscriptable

我做错什么了？
更新
murphy1310的回答解决了！我将代码更改为以下内容，效果很好：

import mysql.connector
config = {
  'user': 'XXXXXXXXXXXXX',
  'password': 'XXXXXXXXXXXXX',
  'host': 'XXXXXXXXXXXXX',
  'database': 'XXXXXXXXXXXXX',
  'raise_on_warnings': True
}
membernum = 9
db = mysql.connector.connect(**config)
if db.is_connected():
    cursor = db.cursor()
    query = "SELECT ticketnum FROM Tickets WHERE membernum={} limit 1".format(membernum)
    cursor.execute(query)
    result = cursor.fetchone()
    if result != None:
        ticketnum = result[0]
        print(ticketnum)
    else:
        print("No results")
    cursor.close
    db.close
else:
    print("Connection error")