python之Django 在 created_at 上注释

我想计算每天在 Django 中创建的记录数，但我做不到。到目前为止，我得到了这个:

data = Reservation.objects\ 
        .order_by('created_at')\ 
        .extra({'dp': "date(created_at)"}) \ 
        .values('dp').annotate(count=Count('id')) 

哪个返回

<QuerySet [{'count': 1, 'dp': datetime.date(2017, 2, 28)}, {'count': 1, 'dp': datetime.date(2017, 2, 28)}, {'count': 1, 'dp': datetime.date(2017, 2, 28)}, {'count': 1, 'dp': datetime.date(2017, 2, 28)}, {'count': 1, 'dp': datetime.date(2017, 3, 1)}, {'count': 1, 'dp': datetime.date(2017, 3, 1)}, {'count': 1, 'dp': datetime.date(2017, 3, 1)}, {'count': 1, 'dp': datetime.date(2017, 3, 2)}, {'count': 1, 'dp': datetime.date(2017, 3, 2)}, {'count': 1, 'dp': datetime.date(2017, 3, 2)}, {'count': 1, 'dp': datetime.date(2017, 3, 2)}, {'count': 1, 'dp': datetime.date(2017, 3, 2)}, {'count': 1, 'dp': datetime.date(2017, 3, 2)}, {'count': 1, 'dp': datetime.date(2017, 3, 2)}, {'count': 1, 'dp': datetime.date(2017, 3, 2)}, {'count': 1, 'dp': datetime.date(2017, 3, 2)}, {'count': 1, 'dp': datetime.date(2017, 3, 2)}, {'count': 1, 'dp': datetime.date(2017, 3, 2)}, {'count': 1, 'dp': datetime.date(2017, 3, 2)}, {'count': 1, 'dp': datetime.date(2017, 3, 2)}, '...(remaining elements truncated)...']> 

我怎样才能一起计算 dp 记录，以便我得到:

<QuerySet [{'count': 4, 'dp': datetime.date(2017, 2, 28)}{'count': 3, 'dp': datetime.date(2017, 3, 1)},.. 

请您参考如下方法:

这应该是最后一个了:

.order_by('dp')