忘れるのでメモ
(たぶんこうなるという例。動作確認はしてない。)
from django.db import models class Author(models.Model): name = models.CharField() book = models.ForeignKey(Book) class Book(models.Model): name = models.CharField() pubdate = models.DateField()
>>> from django.db.models import Count >>> from author.models import Author >>> authors = Author.objects.annotate(num_book=Count('book')).order_by('-num_book') >>> authors[0].num_book 508 >>> authors[0].pk 17