Django, how to filter for a range of rows then pick the one with max date?

Question

Goal:

In here I am filtering for deals with the given id and from those I would like to pick the one with the latest date.

contact.deal_set.filter(deal_id=deal_id).aggregate(Max('deal_start_datetime'))

However this only gives back a dictionary with the max date in it. I need the row though. What am I doing wrong?

Answer 1

Use the .latest method provide for django query sets.

For example in your particular case:

contact.deal_set.filter(deal_id=deal_id).latest('deal_start_datetime')

Django Documentation: https://docs.djangoproject.com/en/dev/ref/models/querysets/#latest

Answer 2

Use this

contact.deal_set.filter(deal_id=deal_id).order_by('-deal_start_datetime')

This will sort queryset by deal_start_datetime in reverse, 0th element is the latest one, you can get it as

latest_contact = contact.deal_set.filter(deal_id=deal_id).order_by('-deal_start_datetime')[0]