Get minimum value field name using aggregation in django

Question

I have a model with some fields like below

class Choclate(models.Model):
    name = models.CharField(max_length=256)
    price = models.IntegerField()

So i want to get the field name that has the lowest price value, so in order to get the lowest price value, we can do like below using Aggregations

from django.db.models import Avg, Max, Min

choclates = Choclate.objects.all()
lowest_price = choclates.aggregate(Min('price'))

So finally how to get the field name, that related to lowest price value in django ?

Answer 1

You can try below code to get exact thing you want

>>> from django.db.models import Min
>>> Choclate.objects.filter().values_list('name').annotate(Min('price')).order_by('price')[0]
(u'First1', 10)
>>>

First1 is the field name having price = 10 which is lowest value.

Documentation Link

Answer 2

If you pass the Min as positional argument, then the field's name is price__min. Otherwise, if you pass it as keyword argument, i.e. aggregate(my_min=Min('price')), then it will be available with the same name as the argument, in this case my_min. Docs

Answer 3

For Min and Max you may order your values (QuerySet result) and grab the first() and last():

chocolate_list = Chocolate.objects.values_list('name', 'price')
min = chocolate_list.order_by('price').first()
max = chocolate_list.order_by('price').last()

PS: Remove the filter() if you are not assigning nothing. With values_list() you are implicitly instancing the QuerySet class

Answer 4

Usage of what @Maciej Gol said:

from django.db.models import Min    

lowest_price = Chocolate.objects.values('price').aggregate(Min('price'))['price__min']