#34728: OR operator on queryset does not work as expected
-------------------------------------+-------------------------------------
Reporter: Kbleser | Owner: nobody
Type: Bug | Status: new
Component: Database layer | Version: 4.2
(models, ORM) |
Severity: Normal | Resolution:
Keywords: queryset OR | Triage Stage:
| Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
Comment (by Mariusz Felisiak):
Replying to [comment:4 René Fleschenberg]:
> Natalia, I disagree. It is not a support request (the reporters problem
was solved by using a different API), but a possible bug in the ORM.
Combining two querysets with {{{|}}} where at least one of them is non-
empty should not result in an empty queryset, IMO. If it can (when?), we
should probably document this.
>
> It also seems to me that the behaviour does not match the note in the
[https://docs.djangoproject.com/en/4.2/ref/models/querysets/#or docs]
about equivalency with {{{Q}}} objects?
Queryset that you
[https://code.djangoproject.com/ticket/34728?replyto=4#comment:1 proposed]
is not the same query that user used in a sample project, I'm not sure how
the ORM could figure it out from:
{{{
Recipe.objects.filter(
Q(ingredients__in=self.ingredients.all()
).annotate(
shared_ingredients=Count("ingredients")
).filter(shared_ingredients__gte=4)
|
Recipe.objects.filter(
Q(tags__in=self.tags.all()) & Q(ingredients__in=self.ingredients.all()
).annotate(
shared_ingredients=Count("ingredients")
).filter(shared_ingredients__gte=2)
}}}
Docs only describe how the OR operator works by rule. The ORM cannot
analyze user queries and rewrite them.
--
Ticket URL: <https://code.djangoproject.com/ticket/34728#comment:7>
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