id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
32151	invalid query SQL created when combining __in and F() in filter	Beda Kosata	nobody	"When a query contains an `__in` filter with `F()` on the right side (I observed it with a ManyToMany relationship), the generated SQL is not correct and causes a SyntaxError. At least for PostgreSQL 12.

Here is a sample project to reproduce the issue:

**models.py**

{{{#!python
from django.db import models

class Author(models.Model):
    name = models.CharField(max_length=32)


class Publisher(models.Model):
    authors = models.ManyToManyField(Author)


class Book(models.Model):
    publisher = models.ForeignKey(Publisher, on_delete=models.CASCADE)
    author = models.ForeignKey(Author, on_delete=models.CASCADE)
}}}

This query:

{{{#!python
list(Book.objects.filter(author__in=F('publisher__authors')))
}}}


then fails with `psycopg2.errors.SyntaxError: syntax error at or near """"ferror_publisher_authors""""`


The problem is that the generated query looks like this:

{{{#!sql
SELECT ""ferror_book"".""id"", ""ferror_book"".""publisher_id"", ""ferror_book"".""author_id""
  FROM ""ferror_book""
  INNER JOIN ""ferror_publisher"" ON (""ferror_book"".""publisher_id"" = ""ferror_publisher"".""id"") 
  INNER JOIN ""ferror_publisher_authors"" ON (""ferror_publisher"".""id"" = ""ferror_publisher_authors"".""publisher_id"") 
WHERE ""ferror_book"".""author_id"" IN ""ferror_publisher_authors"".""author_id""
}}}

This issue is present in both 3.0.10 and 3.1.5. When the same code is run in Django 2.2.16, a correct query is created with brackets around the `""ferror_publisher_authors"".""author_id""` part at the end.

{{{#!sql
SELECT ""ferror_book"".""id"", ""ferror_book"".""publisher_id"", ""ferror_book"".""author_id""
  FROM ""ferror_book""
  INNER JOIN ""ferror_publisher"" ON (""ferror_book"".""publisher_id"" = ""ferror_publisher"".""id"") 
  INNER JOIN ""ferror_publisher_authors"" ON (""ferror_publisher"".""id"" = ""ferror_publisher_authors"".""publisher_id"") 
WHERE ""ferror_book"".""author_id"" IN (""ferror_publisher_authors"".""author_id"")
}}}
"	Bug	new	Database layer (models, ORM)	3.1	Normal				Unreviewed	0	0	0	0	0	0