Does anyone know if there's a way to just select the number of rows matching a query in Django? I have a search I've written that splits results into sets of 40, but I'd like to display the total number of results as well. I could to something like len(Model.objects.filter(name__icontains=search)), but it seems like that would be grossly inefficient (since I'm assuming that would generate a "SELECT * FROM model" and then all of the resulting objects). Any suggestions?
3 Answers
Use count():
>>> Model.objects.count()
42
>>> Model.related_set.count()
102
>>> Model.related_set.filter(blah=42).count()
3
Comments
There are two main ways to handle this:
- Use Django's count() QuerySet method — simply append count() to the end of the appropriate QuerySet
- Generate an aggregate over the QuerySet — Aggregation is when you "retrieve values that are derived by summarizing or aggregating a collection of objects." Ref: Django Aggregation Documentation
The links above are to the applicable sections of Django's documentation.
1 Comment
Andrew
Thanks, aggregate did the trick. It's kind of strange; I had to do an aggregate(Count('id')).count() (counting my count?). I'm happy though as long as it's hopefully only pulling up a number though and not all of the data in the table.
For all row count of a table/model:
pattern:
Model.objects.count()
example:
User.objects.count()
For specific row count of a table/model:
pattern:
Model.objects.filter(user__id=1).count()
example:
User.objects.filter(user__id=1).count()
For further info please visit: https://docs.djangoproject.com/en/4.1/topics/db/aggregation/
