How can I use aggregate functions in Django views?

How can I use aggregate functions in Django views?

You can use Django's annotate() and aggregate() methods to perform calculations on your querysets. For example, to get the average price of products, you can do something like this: Product.objects.aggregate(Avg('price')).

Can you show me an example of using annotate()?

Sure! If you want to count the number of orders for each customer, you can use annotate() like this: Customer.objects.annotate(order_count=Count('orders')).

What if I want to filter the results before aggregating?

You can chain the filter() method before aggregate(). For example: Product.objects.filter(category='Electronics').aggregate(Avg('price')) will give you the average price of electronics.

Are there any performance considerations I should be aware of?

Yes, using aggregate functions can be resource-intensive, especially on large datasets. It's best to limit the data you're aggregating with filters and to use indexes where appropriate.