Django, how to write SQL or ORM to sum something?

I want to count something like this:

input list:

• AAA female 1
• AAA female 2
• BBB male 2
• BBB male 1
• AAA male 1

output list:

• AAA male 1
• AAA female 3
• BBB male 3

Sorry, my english is not good, thanks for everyone who help me.

Answer

Don’t know your exact model struture, but the queries you need to run should be something like the following:

Assuming your model name is “YourModel”, field containing “AAA” or “BBB” is “field_1”, field containing “male” of “female” is “field_2”, and the field containing numeric value is “field_3”

from django.db.models import Sum
YourModel.objects.filter(field_1='AAA', field_2='male').aggregate(sum=Sum('field_3')).get('sum')  # AAA male 1
YourModel.objects.filter(field_1='AAA', field_2='female').aggregate(sum=Sum('field_3')).get('sum')  # AAA female 3
YourModel.objects.filter(field_1='BBB', field_2='male').aggregate(sum=Sum('field_3')).get('sum')  # BBB male 3

I saw from your comment on the question that you want to group on name and gender, then sum their counts. You can do that with annotations as follows:

from django.db.models import Sum
YourModel.objects.values('name', 'gender').annotate(sum=Sum('count'))

Here you group by name and gender with the part values(‘name’, ‘gender’) and annotate each name – gender pair row with the sum of counts.