Re: Using DISTINCT on related model fields

I found a solution from the annotate docs:

A.objects.values('b__name').distinct()

tada! hope this helps someone else later :)

On Jan 10, 3:43 pm, John <theu...@gmail.com> wrote:
> I'm trying to express this query using the Django ORM:
>
> SELECT DISTINCT test_b.name FROM test_a LEFT JOIN test_b ON
> test_a.b_id = test_b.id
>
> using Django (with models 'A' and 'B') all I seem to be able to get is
>
> SELECT DISTINCT test_a.name, test_a.id FROM a INNER JOIN test_b ON
> test_a.b_id = test_b.id
>
> via the query:
>
> A.objects.all().distinct('b__name')
>
> I've tried various changes, including select_related() to try and
> convince it to follow the relation, but no matter what I do it ends up
> using the fields from the A model in the DISTINCT clause rather than
> B.  I assume that part of the problem is that the query I want to
> express does not return an A object, but I can't think of how to use
> the B model to phrase it in the ORM
> (B.objects.all.distinct('name').filter( "has at least one A
> model" ) ? )

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