python - 如何在 django 查询中排序？

Question

我在 django 中有一个名为 User 的表作为自定义用户模型。我有另一个名为 Portfolio 和 ProjectDetail 的模型，它们与我的 User 模型具有 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)

我想查找上传项目数量最多的用户列表或查找作品集数量最多的用户列表。我如何找到按 ProjecDetail 数量或 Portfolio 数量排序的用户列表？

Answer 1

使用annotate对于分组依据:

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')