Opened 6 years ago
Last modified 6 years ago
#30099 closed Bug
Filter by Count annotated inside Subquery — at Version 3
Reported by: | MrFus10n | Owned by: | nobody |
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Component: | Database layer (models, ORM) | Version: | 2.1 |
Severity: | Normal | Keywords: | subquery annotate filter |
Cc: | Simon Charette | Triage Stage: | Ready for checkin |
Has patch: | yes | Needs documentation: | no |
Needs tests: | no | Patch needs improvement: | no |
Easy pickings: | no | UI/UX: | no |
Description (last modified by )
I want to get authors and annotate minimal count of books in category if it is greater than three.
Book and Author models and are not connected with ForeignKey fields (this is abstract and simplified, there is a reason):
Author(models.Model): name = models.CharField(max_length=250) Book(models.Model): author_name = models.CharField(max_length=250) book_category = models.CharField(max_length=250)
Here is simplest query I can get to reproduce:
(Author.objects .annotate(min_valuable_count=Subquery( Book.objects .filter(author_name=OuterRef('name')) .annotate(cnt=Count('book_category')) .filter(cnt__gt=3) .order_by('cnt') .values('cnt')[:1], output_field=models.IntegerField() )))
And I get an error:
psycopg2.ProgrammingError: missing FROM-clause entry for table "U0" LINE 1: ... "core_author" GROUP BY "core_author"."id", "U0"."id" ... ^
Here is SQL:
SELECT "core_author"."id", "core_author"."name", ( SELECT COUNT(U0."book_category") AS "cnt" FROM "core_book" U0 WHERE U0."id" = ("core_author"."chat_id") GROUP BY U0."id" HAVING COUNT(U0."book_category") > 3 ORDER BY "cnt" ASC LIMIT 1) AS "min_valuable_count" FROM "core_author" GROUP BY "core_author"."id", "U0"."id"
If I remove line .filter(cnt__gt=3)
, last GROUP BY
disappears and query stops raising error:
SELECT "core_author"."id", "core_author"."name", ( SELECT COUNT(U0."book_category") AS "cnt" FROM "core_book" U0 WHERE U0."id" = ("core_author"."chat_id") GROUP BY U0."id" HAVING COUNT(U0."book_category") > 3 ORDER BY "cnt" ASC LIMIT 1) AS "min_valuable_count" FROM "core_author" GROUP BY "core_author"."id", "U0"."id"
Is there any way to remove GROUP BY
in outer query without removing .filter(cnt__gt=3)
in subquery?
Change History (3)
comment:1 by , 6 years ago
Description: | modified (diff) |
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Keywords: | Subquery annotate Count filter added |
comment:2 by , 6 years ago
Description: | modified (diff) |
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comment:3 by , 6 years ago
Description: | modified (diff) |
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