Не работает комманда в игровом боте на Discord py, sql

@client.event
async def on_ready():
  cursor.execute("""CREATE TABLE IF NOT EXISTS users (
    name TEXT,
    id INT,
    cash BIGINT,
    rep INT,
    lvl INT,
    upgrade INT
  )""")

  for guild in client.guilds:
    for member in guild.members:
      if cursor.execute(F"SELECT id FROM users WHERE id = {member.id}").fetchone() is None:
        cursor.execute(f"INSERT INTO users VALUES ('{member}', {member.id}, 0, 0, 1 , 10)")
        connection.commit()
      else:
        pass

  connection.commit()
  print('Бот присоеденился') 




@client.command()
async def click(ctx,member: discord.Member = None ):
  global upgrade
  cursor.execute("UPDATE users SET cash = cash + {} WHERE id = {}".format(upgrade, ctx.author.id))
  connection.commit()
  await ctx.send('+ ' + upgrade + ' cash') 

Моя коммандв click не работает. Ошибка :

Traceback (most recent call last):
  File "C:\UsersНикитос\AppData\Local\Programs\Python\Python36\lib\site-packages\discord\ext\commands\core.py", line 85, in wrapped
    ret = await coro(args, **kwargs)
  File "C:\UsersНикитос\Desktop\discordbot.py", line 63, in click
    cursor.execute("UPDATE users SET cash = cash + {} WHERE id = {}".format(upgrade, ctx.author.id))
NameError: name 'upgrade' is not defined

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "C:\UsersНикитос\AppData\Local\Programs\Python\Python36\lib\site-packages\discord\ext\commands\bot.py", line 902, in invoke
    await ctx.command.invoke(ctx)
  File "C:\UsersНикитос\AppData\Local\Programs\Python\Python36\lib\site-packages\discord\ext\commands\core.py", line 864, in invoke
    await injected(ctx.args, **ctx.kwargs)
  File "C:\UsersНикитос\AppData\Local\Programs\Python\Python36\lib\site-packages\discord\ext\commands\core.py", line 94, in wrapped
    raise CommandInvokeError(exc) from exc
discord.ext.commands.errors.CommandInvokeError: Command raised an exception: NameError: name 'upgrade' is not defined```