python - 我如何将两个字段的总和与 Django 中同一模型上的另一个字段进行比较

Question

这是我的模型

class Wallet(models.Model):
    """
    Keep track of the monetary values of a company's wallet
    """
    serializer_class = WalletSocketSerializer

    company = models.OneToOneField(Company, verbose_name=_('company'))
    packaged_credits = models.BigIntegerField(_('packaged credits'), default=0)
    purchased_credits = models.BigIntegerField(_('purchased credits'), default=0)
    low_credits_threshold = models.BigIntegerField(default=0)

现在我想在总积分低于阈值时发送警报，这相当于在此 SQL 中获取所有低钱包

select * from wallets_wallet where (packaged_credits + purchased_credits) < low_credits_threshold;

我想知道如何在 Django 中执行它，现在我已经尝试了以下方法，它有效，但我认为它应该以更 Django 的方式完成:

low_wallets = []
        for wallet in Wallet.objects.all():
            if wallet.packaged_credits + wallet.purchased_credits < wallet.low_credits_threshold:
                low_wallets.append(wallet)

Answer 1

from django.db.models import F

low_wallets = Wallet.objects.filter(
    low_credits_threshold__gt=F('packaged_credits')+F('purchased_credits')
)