Using Django to summarize Report

问题

I'm trying to produce a table that will show the total maturity amounts for each financial institution that a plan has.

A plan is the term I use for person. So each person can have multiple investments. I'm having trouble creating a table that will do this correctly.

Currently I have a report that displays each investment sorted by Maturity Date, i.e. 2011,2012, etc.

At the bottom I would like to place this summary table, but my query displays duplicates of each financial institution, due to being able to have multiple investments.

My current query:

list = Investment.objects.all().filter(plan = plan).order_by('financial_institution').filter(maturity_date__gte= '%s-1-1' % current_year).distinct()

This will output:

• TD Bank $10k
• TD Bank $10k
• Scotia Bank $10k
• Etc

But I'd like:

• TD Bank $20k
• Scotia Bank $10k
• Etc

回答1:

So, you want to aggregate the values of the investments for a plan:

from django.db.models import Sum
my_plan.investment_set.filter(
    maturity_date__gte=whenever
).values('financial_institution').annotate(Sum('value'))

来源：https://stackoverflow.com/questions/7600431/using-django-to-summarize-report