[Answered ]-Django select rows with duplicate field values for specific foreign key

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1👍

✅

It sounds to me as though you want to execute a SQL query something like this:

SELECT l1.* FROM myapp_literal AS l1,
                 myapp_literal AS l2
WHERE l1.id <> l2.id
  AND l1.name = l2.name
  AND l1.concept = l2.concept
  AND l1.id NOT IN (SELECT main_name FROM myapp_concept)
GROUP BY l1.id

Well, in cases where the query is too complex to easily express in Django’s query language, you can always ask Django to do a raw SQL query—and this may be one of those cases.

👤Gareth Rees

1👍

If I understand your question you want:

  1. All Literal objects that are not ForeignKey’d to Concept.
  2. From that set, select those where the name and the concept is the same.

If so, I think this should work:

For the first part:

q = Literal.objects.exclude(pk__in=Concept.objects.values_list('id', flat=True))

EDIT:

Based on excellent feedback from Jan, I think for #2 you would need to use raw SQL.

👤Burhan Khalid

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