Question

I have such model and query

class Employer(Models.model)
    name = ...

class JobTitle(Models.model)
    name = ...
    employer = models.ForeignKey(Employer)

and query is

Employer.objects.select_related('jobtitle')
                      .filter(jtt__activatedate__range=[startdate,enddate])
                      .annotate(jtt_count=Count('jobtitle'))
                      .order_by('-jtt_count')[:5]

As you see it returns 5 employer list which has maximum number of jobtitles which are related to that employer and whose activation date is in some certain range.

However, I also want to get the total number of jobtitles of each employer in that query.
Of course I may loop over each employer and make such query JobTitle.objects.filter(employer = emp) and taking length of that query but it is bad solution.

How can I achive this in that query?
Although it may not be possible to get both total number and filtered number of job titles, I may get the jobttiles of each emplyoer such that len(emp.jobtitle) however it also didn’t work.

Thanks

Answer 1

Try the extra lookup. So, in your case it may be like this:

.extra(
    select={
        'jobtitle_count': 'SELECT COUNT(*) FROM YOURAPP_jobtitle WHERE YOURAPP_jobtitle.employer_id = YOURAPP_employer.id'
    },
)