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Python

Posted by jacinator
jacinator
11,936 Points

Django annotation doesn't make sense

I've been stuck on this for a little while now, but I can't figure out Django annotation. The error that I keep getting is "Didn't find the right average." If someone can tell me what I am doing wrong and why it is wrong, I would greatly appreciate it.

https://teamtreehouse.com/library/django-orm/total-control/annotate is the code challenge that this is from.

import datetime

from django.db.models import Q, Avg
from django.shortcuts import render, get_object_or_404

from . import models


def good_reviews(request):
    reviews = models.Review.objects.filter(rating__gte=3)
    return render(request, 'products/reviews.html', {'reviews': reviews})


def recent_reviews(request):
    six_months_ago = datetime.datetime.today() - datetime.timedelta(days=180)
    reviews = models.Review.objects.exclude(created_at__lt=six_months_ago)
    return render(request, 'products/reviews.html', {'reviews': reviews})


def product_detail(request, pk):
    product = get_object_or_404(models.Product, pk=pk)
    four_weeks_ago = datetime.datetime.today() - datetime.timedelta(weeks=4)
    reviews = product.review_set.filter(
        Q(rating__gte=8)|Q(created_at__gte=four_weeks_ago)
    ).order_by('-created_at').all()
    return render(request, 'products/product_detail.html', {'product': product, 'reviews': reviews})


def product_list(request):
    # This is my code here. Prior it was
    # products = models.Product.objects.all()
    products = models.Product.objects.all().annotate(
        avg_rating=Avg('review', distinct=True)
    )
    return render(request, 'products/product_list.html', {'products': products})

1 Answer

jacinator
jacinator
11,936 Points

I needed to get the Avg on review.rating, not review.

def product_list(request):
    products = models.Product.objects.all().annotate(
        avg_rating=Avg('review__rating', distinct=True)
    )
    return render(request, 'products/product_list.html', {'products': products})