Hi Daniel,
On Sun, 2006-07-16 at 09:07 +0000, [EMAIL PROTECTED] wrote:
> Hi.
>
> This is probably trivial, but I've not managed to find the solution.
> How do I filter objects based on the count of a ManyToManyField?
>
> My example:
>
> I have two classes -- Blog and Submission:
>
> class Blog( models.Model ):
> entries = models.ManyToManyField( Submission )
>
> class Submission( models.Model ):
> [... whatever ]
>
> I want to fetch a list of all Blog instances which have at least one
> Submission , i.e. entries.count() > 0. Changing the model is not an
> option.
>
> I've been trying all kinds of permutations of filter, entries, count,
> gt, etc, such as:
> Blog.objects.filter(entries__count__gt = 0)
I'll agree this one isn't too obvious (until you see the answer):
Blog.objects.filter(entries__isnull = False)
will do what you want (have a look at the underlying SQL query is you
are interested in seeing that it really works as advertised).
Regards,
Malcolm
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