#24770: Model instances are dropped by annotate when reverse foreign key is
empty.
----------------------------------------------+--------------------
Reporter: Ian-Foote | Owner: nobody
Type: Bug | Status: new
Component: Database layer (models, ORM) | Version: 1.8
Severity: Normal | Keywords:
Triage Stage: Unreviewed | Has patch: 0
Easy pickings: 0 | UI/UX: 0
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I ran across an odd interaction between `annotate`, `Sum`, `Case`, `When`
and a reverse `ForeignKey`. I've prepared a [https://github.com/Ian-Foote
/django-annotate-bug/blob/master/bug/tests/test_query.py#L10-L24 minimal
testcase].
The query generated by the annotate looks like:
{{{
SELECT "bug_post"."id", "bug_post"."created", SUM(CASE WHEN
"bug_comment"."created" > ("bug_post"."created") THEN 1 ELSE 0 END) AS
"unread_comments" FROM "bug_post" INNER JOIN "bug_comment" ON (
"bug_post"."id" = "bug_comment"."post_id" ) GROUP BY "bug_post"."id",
"bug_post"."created"
}}}
I initially ran into this on postgres, but my minimal testcase also shows
it on sqlite.
--
Ticket URL: <https://code.djangoproject.com/ticket/24770>
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