What are some advanced examples of aggregation functions in Django?

What are some advanced examples of aggregation functions in Django?

Django provides several advanced aggregation functions like Count, Sum, Avg, Max, and Min. For example, you can use annotate() with Count to get the number of related objects.

Can you show me a code example using Count with annotate?

Sure! Here's an example:

from django.db.models import Count

# Assuming you have a model called Book and you want to count the number of reviews:
Book.objects.annotate(num_reviews=Count('reviews'))

What about using Sum and Avg in a query?

You can use Sum and Avg similarly. For instance:

from django.db.models import Sum, Avg

# To get the total price of all books:
Book.objects.aggregate(total_price=Sum('price'))

# To get the average price:
Book.objects.aggregate(average_price=Avg('price'))

Are there any other advanced functions I should know about?

Yes, you might also explore StdDev, Variance, and GroupBy for more complex queries. These can help in statistical analysis.