Django 如何过滤没有评论的帖子

让我们开始讨论这个问题。 我有一个观点，应该向我展示所有未回答的问题，这些问题是在4小时后提出的。我已经试了很多，但都不管用，所以我问这个问题。 我应该如何过滤没有评论的帖子

views.py

def subject_unanswered(request, slug):
    subject = Subject.objects.filter(slug=slug).first()
    four_hours = datetime.today() - timedelta(hours=4)
    posts = Post.objects.filter(subject=subject, created_at__lt=four_hours).order_by('-created_at')
    args = {
        'subject'       : subject,
        'posts'         : posts,
        }
    return render(request, 'ask/subject_time_ago.html', args)

models.py

class Comment(models.Model):
    related_post    = models.ForeignKey(Post, on_delete=models.CASCADE)
    comment         = models.TextField(max_length=1000)
    created_by      = models.ForeignKey(MyUser, on_delete=models.CASCADE, related_name='comments')
    created_at      = models.DateTimeField(auto_now_add=True)
    likes           = models.ManyToManyField(MyUser, related_name='comment_likes', blank=True)

class Post(models.Model):
    slug        = models.SlugField(unique=True, max_length=200)
    subject     = models.ForeignKey(Subject, on_delete=models.CASCADE)
    topic       = models.CharField(max_length=200)
    text        = models.TextField(max_length=5000)
    created_by  = models.ForeignKey(MyUser, on_delete=models.CASCADE, related_name='posts')
    created_at  = models.DateTimeField(auto_now_add=True)
    likes       = models.ManyToManyField(MyUser, related_name='likes', blank=True)

---

您可以通过反向关系进行过滤，如

Post.objects.filter(comment__isnull=True)

这将返回所有没有评论的帖子