Query for top x elements in Django

问题

I have two models such that

class JobTitle(models.Model):
     name = models.CharField(max_length=1000)

class Employer(models.Model): 
     jobtitle = models.ForeignKey(JobTitle,unique=False,null=True)

As you see, one employer may have many jobtitles. I try to make a query to get top 5 employers whose number of job titles is maximum

How can I achive this is Django ?

Thanks

回答1:

Employer.objects.values('id').annotate(jobtitle_count=Count('jobtitle')).order_by('-jobtitle_count')[:5]

回答2:

from django.db.models import Count

Employer.objects.annotate(Count('jobtitle')).order_by('-jobtitle__count')[:5]

来源：https://stackoverflow.com/questions/6436937/query-for-top-x-elements-in-django