You could do User.objects.exclude(groups__in=Group.objects.all
().query) which will actually generate a subquery.
Alex
On Dec 2, 10:45 am, Thomas Guettler <[EMAIL PROTECTED]> wrote:
> Hi,
>
> I want to get all objects where the corresponding many-to-many field is
> empty.
>
> Example: get all users without a group
>
> My solution:
> User.objects.exclude(groups__in=Group.objects.all())
>
> I think this is not optimal, since Group.objects.all() gets evaluated.
>
> Resulting SQL:
>
> SELECT "auth_user"."id", "auth_user"."username",
> "auth_user"."first_name", "auth_user"."last_name",
> "auth_user"."email", "auth_user"."password", "auth_user"."is_staff",
> "auth_user"."is_active", "auth_user"."is_superuser",
> "auth_user"."last_login", "auth_user"."date_joined" FROM "auth_user" WHERE
> NOT ("auth_user"."id" IN (SELECT U1."user_id" FROM "auth_user" U0
> INNER JOIN "auth_user_groups" U1 ON (U0."id" = U1."user_id")
> WHERE U1."group_id" IN (9, 10, 11, 8))) LIMIT 21
>
> Any better way to do this?
>
> Should the extra() method be used for this?
>
> Thomas
>
> --
> Thomas Guettler,http://www.thomas-guettler.de/
> E-Mail: guettli (*) thomas-guettler + de
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