user_id takes value None after function call (telebot, sqlite3)

Question

I am making a telegram bot using the telebot library. This function retrieves the city of residence, which was previously selected by the user in the city_living variable, from the SQL3 database.

def get_city_living(user_id: int):
        with sqlite3.connect('server.db') as conn:
            cursor = conn.cursor()
            cursor.execute('''
            CREATE TABLE IF NOT EXISTS users (
                user_id INTEGER PRIMARY KEY,
                first_seen TIMESTAMP DEFAULT CURRENT_TIMESTAMP, 
                city_living TEXT DEFAULT 'null'
                )
                ''')
            city = cursor.execute('SELECT city_living FROM users WHERE user_id=?', (user_id,)).fetchone()
            return city[0]

if callback.data == 'profile':
            user_id=callback.message.from_user.id
            kb = types.InlineKeyboardMarkup(row_width=1)
            item1 = types.InlineKeyboardButton(text=' Назад в главное меню', callback_data='back1') #back to main menu
            name = f' Имя: {callback.from_user.first_name}'
            buys = '\n Совершено покупок: ' + str(buy)
            cityl = '\n  Город: ' + get_city_living(user_id) #City: 
            kb.add(item1)
            bot.edit_message_text(chat_id=callback.message.chat.id, message_id=callback.message.id, text=name+buys+cityl, reply_markup=kb)

Line 129 is the return city[0]. Why does this error occur? How to fix it?

File "<string>", line 492, in bot_message
File "<string>", line 129, in 
get_city_living
TypeError: 'NoneType' object is not 
subscriptable

Answer 1

To retrieve some data from the database, you should insert data into the table first. Your function get_city_living() creates the table if it does not exist and retrieves data from the table. But it doesn't insert anything into the table. And I don't see any other code here that would do it.

It looks like you don't have entries in the 'users' table, that's why the function returns None.