Django:Group澄清

时间:2011-03-03 15:58:47

标签: django django-models django-views

我有一个看起来像这样的views.py:

category = Category.objects.get(id=categoryid)    
#posts = get_list_or_404(Post, category=categoryid)
posts = Post.objects.filter(category=categoryid,is_comment=0).order_by('-published')
all_posts = []

for p in posts:
    all_posts += [(x.id, x.marked_read_on, p, \
                    Unread.objects.filter(marked_read_on__isnull=True, \
                                          user=request.user,comment__post=p.id).count(), \
                    Unread.objects.filter(user=request.user,comment__post=p.id).count(), \
                    #1
                ) \
                #for x in p.unread_set.filter(post=p.id)]
                for x in p.unread_set.filter(post=p.id).annotate(Count('post')).order_by('post')]

对于for x in p.unread_set.filter(post=p.id).annotate(Count('post')).order_by('post')]我得到下面的sql查询:(没有错误)

SELECT `message_unread`.`id`, `message_unread`.`user_id`, `message_unread`.`post_id`, `message_unread`.`comment_id`, `message_unread`.`category_id`, `message_unread`.`marked_unread_on`, `message_unread`.`marked_read_on`, COUNT(`message_unread`.`post_id`) AS `post__count` FROM `message_unread` WHERE (`message_unread`.`post_id` = 4 AND `message_unread`.`post_id` = 4 ) GROUP BY `message_unread`.`id` ORDER BY `message_unread`.`post_id` ASC

我只想要这个部分:     GROUP BY message_unread.id

成为:     message_unread

我只是想通过post_id对结果进行分组。仅供参考,应用程序的名称是“消息”,这就是查询具有“message_”前缀的原因。

我该怎么做?

更新,我的models.py看起来像这样:

id

1 个答案:

答案 0 :(得分:2)

以下是unread.objects.filter(post=p.id).values(message_unread.id).order_by().annotate(Count('post'))

分组的查询
>>> from django.db.models import Count
>>> m=Unread.objects.filter(post__id='1').values('id').order_by().annotate(Count('post'))
>>> m
[{'id': 1L, 'post__count': 1}]
>>> m.values()
[{'marked_read_on': datetime.datetime(2011, 3, 3, 22, 3, 33), 'user_id': 1L, 'comment_id': 1L, 'post_id': 1L, 'marked_unread_on': datetime.datetime(2011, 3, 3, 22, 3, 29), 'category_id': 1L, 'id': 1L, 'post__count': 1}]

以下查询

>>> print m.query
SELECT `mytest_unread`.`id`, COUNT(`mytest_unread`.`post_id`) AS `post__count` FROM `mytest_unread` WHERE `mytest_unread`.`post_id` = 1  GROUP BY `mytest_unread`.`id`, `mytest_unread`.`id` ORDER BY NULL