python - 获取所有对象的最新相关对象

Question

假设我有以下模型：

from django import models

class Post(models.Model):
    user = models.ForeignKey(to=User, on_delete=CASCADE)
    created = models.DatetimeField(auto_now_add=True)

我想从一组用户那里获取一些关于最近发布的信息（例如喜欢）

posts = User.objects.filter(**params).annotate(most_recent_post=Max('post__created')).annotate(likes=Count('post__likes', filter=Q(post__created=F('most_recent_post'))

当我尝试进行此查询时，出现以下错误： OperationalError: misuse of aggregation function MAX()

Answer 1

class Post(models.Model):
    user = models.ForeignKey(User, on_delete=CASCADE)
    created = models.DatetimeField(auto_now_add=True)
    class Meta:
        ordering = ['-created'] # ordering Post by created date DESC 
def recent(request):
    user = request.user
    recent_post = user.post_set.all().first() # get the recent post
    counter = user.post_set.all().count() # count all posts by this user

Answer 2

试试这个来获取最近的帖子：

posts = Post.objects.order_by('-id').all()

计数用途：

posts = Post.objects.order_by('-id').all().count()