如何在Django查询中排序？

Question

在django中有一个名为User as custom User model的表。 我有另一个模型叫做Portfolio和ProjectDetail，它们与我的User模型有ForeignKey关系。表结构如下：

class ProjectDetail(models.Model):
    user = models.ForeignKey(settings.AUTH_USER_MODEL)
    title = models.TextField()
    category = models.CharField(max_length=50, choices=CATEGORY_CHOICES)
    description = models.TextField(null=True, blank=True)
    vote_count = models.IntegerField(default=0) 

class Portfolio(models.Model):
    user = models.ForeignKey(settings.AUTH_USER_MODEL)
    project = models.ForeignKey(ProjectDetail, null=True, blank=True)
    description = models.TextField(null=True, blank=True)

用户模型为：

class User(AbstractBaseUser, PermissionsMixin):
    username = models.CharField(_('Username'), unique=True, max_length=100, blank=False, null=False,
        help_text=_('20 characters or fewer. Letters, numbers and -/_ characters, no capitals, no spaces'),
    )
    first_name = models.CharField(_('First Name'), max_length=30, blank=True, null=True)
    middle_name = models.CharField(_('Middle Name'), max_length=30, blank=True, null=True)
    last_name = models.CharField(_('Last Name'), max_length=30, blank=True, null=True)
    about_yourself = models.TextField(null=True, blank=True)

我想找到用户与上传项目的最大数量或找到用户与投资组合的最大数量的列表。如何找到按ProjecDetail或Portfolio数量排序的用户列表？你知道吗

Answer 1

使用annotate作为分组依据：

from django.db.models import Count

#group by portfolios count
User.objects.annotate(portfolios=Count('portfolio')).order_by('portfolios')
#group by projects count
User.objects.annotate(projects=Count('portfolio__project')).order_by('projects')