python - Django group by date and count per category -

example models

class category(models.model)     name = models.charfield()  class categoryitem(models.model):     category = models.foreignkey(category)     name = models.charfield()     quantity = models.intfield()     @ = models.datetimefield()   categories:     1, category #1     2, category #2     3, category #3  items:     id,name,category_id,quantity,at     1,item #1,1,100,2017.1.1     2,item #2,1,200,2017.1.3     3,item #3,1,300,2017.1.3     4,item #4,2,400,2017.1.10     5,item #5,3,500,2017.1.10 

how can annotate day , count "quantity" per category

like this

 2017.1.1     - category #1         - quantity: 100  2017.1.3     - category #1         - quantity: 500  2017.1.10     - category #2         - quantity: 400     - category #3         - quantity: 500 

if understand question, want django query group , count (and inner join).

try this:

categoryitem.objects.filter(categoryitem__category__isnull=false).values('at,name').annotate(total=count('quantity')).order_by('at')