#26194: WHERE EXISTS / WHERE NOT EXISTS clause without using QuerySet.extra
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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
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Changes (by charettes):
* resolution: invalid => duplicate
Comment:
I'm not sure the query can be considered equivalent given the `LEFT JOIN`
will return duplicate rows for parent with multiple children.
`Parent.objects.filter(child=None).distinct()` should return the same
results but I wouldn't be surprised if it performed worse than the
original `EXISTS` query.
I'll re-close as duplicate of #25789 instead.
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Ticket URL: <https://code.djangoproject.com/ticket/26194#comment:3>
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