Django 1.6如何同时正确注释Count（）和Sum（）？

简单描述：

#for each q in Question , q.votes is correct
Question.objects.annotate(votes=Sum('vote__value')) 
#add a Count annotate, q.answers is correct, while q.votes not.
Question.objects.annotate(votes=Sum('vote__value', distinct=True),answers=Count('answer', distinct=True),)

如果我想同时注释Count（）和Sum（），怎么做？因此，我可以这样做：

qs = Question.objects.annotate(votes=Sum('vote__value', distinct=True),answers=Count('answer', distinct=True),)
for q in qs:
    #do something with q.votes and q.answers in a template
    #this will be convenient.

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如果需要，下载测试项目代码。测试函数位于raw.tests.test（）中。

感谢您的支持。他提醒我。我想到了额外的：

qs3 = Question.objects.extra(
    select={
    'answers': 'SELECT COUNT(*) FROM raw_answer WHERE raw_answer.question_id = raw_question.id',
    'votes':'SELECT SUM(value) FROM raw_vote WHERE raw_vote.question_id = raw_question.id',
    },

---

这样就可以了

对于Django 1.11，您可以使用

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你将如何为它编写一个SQL查询？@anuragal我不熟悉SQL。你能举个例子吗？

distinct=True

应该从

Sum

注释中删除。QuerySet实际上可以很好地处理这两个注释。

votes = Vote.objects.filter(question=OuterRef('pk').order_by().values('question')
sum_votes = votes.annotate(s=Sum('value')).values('s')

answers = Answer.objects.filter(question=OuterRef('pk').order_by().values('question')
count_answers = answers.annotate(c=Count('*')).values('c')

qs = Question.objects.annotate(votes=Subquery(sum_votes),
                               answers=Subquery(count_answers))