django_orm_aggregate_average_price_quickstart.py

1from django.db import models
2from django.db.models import Avg
3
4class Author(models.Model):
5    name = models.CharField(max_length=100)
6    age = models.IntegerField()
7
8class Publisher(models.Model):
9    name = models.CharField(max_length=300)
10
11class Book(models.Model):
12    name = models.CharField(max_length=300)
13    pages = models.IntegerField()
14    price = models.DecimalField(max_digits=10, decimal_places=2)
15    rating = models.FloatField()
16    authors = models.ManyToManyField(Author)
17    publisher = models.ForeignKey(Publisher, on_delete=models.CASCADE)
18    pubdate = models.DateField()
19
20class Store(models.Model):
21    name = models.CharField(max_length=300)
22    books = models.ManyToManyField(Book)
23
24# Quickstart usage of aggregation:
25# Calculate the average price of all books.
26average_price = Book.objects.all().aggregate(Avg("price"))
27# Output: {'price__avg': 34.35}