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Aggregations | Complex Queries
Django ORM Ninja: Advanced Techniques for Developers
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Django ORM Ninja: Advanced Techniques for Developers

Django ORM Ninja: Advanced Techniques for Developers

1. Introduction to Django ORM
2. Models, datatypes, and fields
3. Queries
4. Relations
5. Complex Queries
6. Advanced

Aggregations

Do you remember that aggregations in SQL are used to compute a single result from a set of input values. Let's remind some common aggregation functions: COUNT, SUM, AVG, MAX, MIN.

At the same time, Aggregation in Django ORM is a powerful tool to perform calculations over query sets, enabling you to summarize or analyze data efficiently. It allows for operations like counting, averaging, summing, etc., across a set of records.

Basic Aggregation Examples

This query counts how many books each author has written.

Complex Aggregation

Finds the latest publication date for each author.

Aggregation with Filters

Aggregates the total pages of all books in the "Fantasy" genre.

1. What is the primary use of aggregation functions in SQL?
2. What does the following Django ORM query do? Author.objects.annotate(latest_publication=Max('books__publication_date'))
3. Which Django ORM query is used to aggregate the total pages of all books in the 'Fantasy' genre?

What is the primary use of aggregation functions in SQL?

Selecione a resposta correta

What does the following Django ORM query do? Author.objects.annotate(latest_publication=Max('books__publication_date'))

Selecione a resposta correta

Which Django ORM query is used to aggregate the total pages of all books in the 'Fantasy' genre?

Selecione a resposta correta

Tudo estava claro?

Seção 5. Capítulo 3
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