#29214: Invalid SQL generated when annotating a subquery with an outerref to an
annotated field.
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Reporter: Oskar Persson | Owner: nobody
Type: Bug | Status: new
Component: Database layer | Version: master
(models, ORM) |
Severity: Normal | Resolution:
Keywords: queryset | Triage Stage: Accepted
annotations |
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
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Comment (by Simon Charette):
Chetan, almost correct. The query will not necessarily involve generating
an `INNER JOIN` but it happens to do so in this case.
Most of the logic lives in
[https://github.com/django/django/blob/a6b3938afc0204093b5356ade2be30b461a698c5/django/db/models/sql/compiler.py#L1513-L1553
SQLUpdateCompiler] but the idea is that if the backend supports it the
whole filtering part of the queryset will be pushed down to a subquery,
`JOIN`s included, and filtered against using `pk IN`.
This will be way trickier to implement for subqueries and I'm starting to
wonder if we didn't get it wrong in the first place by making
`OuteRef('outerqs__lookup')` result in a new `JOIN` in the outer query
instead of encapsulating it in the subquery. The way we do it right now
breaks aggregation in subtle ways #29214 and happens to break update as
well as we came to discover.
If the `JOIN` was always encapsulated in the subquery in the first place
it would solve this ticket, #29214 and I suspect it would make
implementing #28296 way easier.
--
Ticket URL: <https://code.djangoproject.com/ticket/29214#comment:14>
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