How Can I Perform Group By Queries in Django Using Aggregation?

Group By Queries in Django

Without patching Django's queryset API, you can achieve group by functionality using the ORM's aggregation features.

Aggregation using Values and Count

To group the results by a specific field and count the occurrences of each group, use the following syntax:

from django.db.models import Count
result = (Members.objects
    .values('designation')
    .annotate(dcount=Count('designation'))
    .order_by()
)

This will return a queryset with the results grouped by the designation field, along with the count of each designation. The output will be a list of dictionaries, each containing the designation and dcount (count of designations).

Including Multiple Fields in Results

To include multiple fields in the results, simply add them as arguments to the values() function:

    .values('designation', 'first_name', 'last_name')

References

• [Django documentation: values()](https://docs.djangoproject.com/en/stable/ref/models/querysets/#values)
• [Django documentation: annotate()](https://docs.djangoproject.com/en/stable/ref/models/querysets/#annotate)
• [Django documentation: Count](https://docs.djangoproject.com/en/stable/ref/models/lookups/#count)
• [Django documentation: Aggregation](https://docs.djangoproject.com/en/stable/topics/db/aggregation/)
• [Django documentation: Interaction with default ordering or order_by()](https://docs.djangoproject.com/en/stable/topics/db/aggregation/#interaction-with-default-ordering-or-orderby)

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