Django - 多个模型字段的总和

Question

我如何在这里添加每个模型的总和？ 最后，我只想为所有 3 个模型的所有 up_votes /down_votes 设置一个值。 请参阅下面的示例：

def calc_user_feedback():
    users = User.objects.all()
    try:
        for user in users:
            fed_qry_up_votes = Model1.objects.filter(author=user).aggregate(Sum('up_vote')) + \
                               Model2.objects.filter(author=user).aggregate(Sum('up_vote')) + \
                               Model3.objects.filter(author=user).aggregate(Sum('up_vote'))
            fed_qry_down_votes = Model1.objects.filter(author=user).aggregate(Sum('down_vote')) + \
                               Model2.objects.filter(author=user).aggregate(Sum('down_vote')) + \
                               Model3.objects.filter(author=user).aggregate(Sum('down_vote'))

            logger.info("Overall user feedback calculated successfully.")
    except:
        logger.info("Error processing task: 'Calculate user feedback', please investigate")

Answer 1

假设author在每个模型上都没有设置related_name ：

from django.db.models import F, Sum

users = (
    User.objects.annotate(up_votes_1=Sum("model1_set__up_vote"))
    .annotate(up_votes_2=Sum("model2_set__up_vote"))
    .annotate(up_votes_3=Sum("model3_set__up_vote"))
    .annotate(total=F("up_votes_1") + F("up_votes_2") + F("up_votes_3"))
)

现在您可以遍历用户并获得每个用户的总数。