获取事件列表+模型Django中的计数? [英] Get list of occurrences + count in a model Django?
问题描述
想象一下我有以下模型:
Imagine I have the following model:
class Person(models.Model):
...other stuff...
optional_first_name= models.CharField(max_length=50, blank=True)
如何编写一个请求,以递减的顺序返回最流行的名称数组及其计数,而忽略空名称?
How would I go about writing a request that returns an array of the most popular names, in decreasing order of occurence, with their counts, while ignoring the empty names?
即对于具有13个Leslies,8个Andys,4月3日,1个Ron和18个尚未指定名字的人的数据库,输出为:
i.e. for a database with 13 Leslies, 8 Andys, 3 Aprils, 1 Ron and 18 people who haven't specified their name, the output would be:
[('leslie ',13),('andy',8),('april',3),('ron',1)]
[('leslie', 13), ('andy', 8), ('april', 3), ('ron', 1)]
我能得到的最接近的是通过执行以下操作:
The closest I can get is by doing the following:
q= Person.objects.all()
q.query.group_by=['optional_first_name']
q.query.add_count_column()
q.values_list('optional_first_name', flat= True)
但是仍然不是我想要的。
But it's still not quite what I want.
推荐答案
经过一番挖掘,终于找到了:
After some digging, finally found out:
Person.objects.values('optional_first_name').annotate(c=Count('optional_first_name')).order_by('-c')
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