On 11/27/06, halmcelroy <[EMAIL PROTECTED]> wrote: > > In SQL this would translate as: > SELECT * FROM A WHERE ID NOT IN (SELECT ID FROM B) ... > for.eg. A.objects.filter().exclude(this__not_in=[.. some list of > objects that I want to exclude]) > > Can anyone throw some light on how to use the models API to get the > above done?
Ok; step one, drop the redundant filter() and the double negatives. The purpose of exclude() is to provide the NOT clause; so, what you want is: A.objects.exclude(id__in=[...]) i.e., get a list of all A's where A.id is not in [..list of ids..]. The empty filter() in your example is not required; it's a no-op. The exclude clause takes all the query arguments, composes them as a query, then wraps them in a NOT. Step Two; getting the subselect. Generally speaking, subselects such as the one you want can be achieved using two queries: b = B.objects.filter(...query conditions...) A.objects.exclude(id__in=[obj.id for obj in b]) There are some ways that you could compress this into a single query using the extra() clause, but these are not as pretty and involve some hand generated SQL snippets. Yours, Russ Magee %-) --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-users@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/django-users?hl=en -~----------~----~----~----~------~----~------~--~---
