#26194: WHERE EXISTS / WHERE NOT EXISTS clause without using QuerySet.extra
-------------------------------------+-------------------------------------
Reporter: john-parton | Owner: nobody
Type: Uncategorized | Status: closed
Component: Database layer | Version: 1.9
(models, ORM) |
Severity: Normal | Resolution: duplicate
Keywords: QuerySet.extra | Triage Stage:
| Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
Comment (by john-parton):
Thanks for looking into this.
Implementing a feature like `.filter(models.Exists(somerel__col=val))` as
mentioned by akaariai in reference to #25789 would fix my issue.
I tried `Parent.objects.filter(child=None).distinct()` and it resulted in
a query that was about 3 times as slow as the `NOT EXISTS` query. This is
definitely better than my attempt with the subquery (which was about 2000
times as slow), but it's still irksome that I can't easily compose the
query using the ORM.
I couldn't find #25789 because I was looking for tickets with the
"QuerySet.extra" keyword. Can we add that keyword to #25789?
--
Ticket URL: <https://code.djangoproject.com/ticket/26194#comment:4>
Django <https://code.djangoproject.com/>
The Web framework for perfectionists with deadlines.
--
You received this message because you are subscribed to the Google Groups
"Django updates" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To post to this group, send email to [email protected].
To view this discussion on the web visit
https://groups.google.com/d/msgid/django-updates/069.2b6b41b3436025c6a9e93647174011ca%40djangoproject.com.
For more options, visit https://groups.google.com/d/optout.
