aggregate_tags.py

from django import template
from django.db.models import Sum, Avg, Max, Min, Count

register = template.Library()


@register.filter
def sum(queryset, field):
    return queryset.aggregate(sum_value=Sum(field)).get('sum_value')


@register.filter
def avg(queryset, field):
    return queryset.aggregate(avg_value=Avg(field)).get('avg_value')


@register.filter
def min(queryset, field):
    return queryset.aggregate(min_value=Min(field)).get('min_value')


@register.filter
def max(queryset, field):
    return queryset.aggregate(max_value=Max(field)).get('max_value')


@register.filter
def count(queryset, field):
    return queryset.aggregate(count_value=Count(field)).get('count_value')