Django“order_by”不包括第一项

Question

我有这个模型，我需要每天00:00自动重置或Purchased.bought_today

models.py

class Purchased(models.Model):
    user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.DO_NOTHING)
    collection = models.ForeignKey(Collection, on_delete=models.DO_NOTHING)
    last_purchased = models.DateTimeField(default=datetime.now) 
    purchased_today = models.IntegerField(default=0)

每当我登录时，我都想用信号重置它

但是没有找到

models.py

from django.contrib.auth.signals import user_logged_in
from django.dispatch import receiver


class Purchased(models.Model):
    user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.DO_NOTHING)
    collection = models.ForeignKey(Collection, on_delete=models.DO_NOTHING)
    last_purchased = models.DateTimeField(default=datetime.now) 
    purchased_today = models.IntegerField(default=0)


@receiver(user_logged_in)
def purchased_today_login(request, **kwargs):
today = datetime.now().strftime("%Y-%m-%d")
if purchased.last_purchased.date().strftime("%Y-%m-%d") != today:
       purchased_today = 0
       subscription.save() 
       user_logged_in.connect(purchased_today_login)

如果成功的话，那将是非常好的

我该怎么做