values_list of ordered annotated QuerySet

[Andreas Pfrengle]

Hello,

I want to annotate a Queryset, order it by the annotated field and
then return a simple (ordered) values_list of the ids of the objects:

Wizard.objects.filter(**filterargs).annotate(wpower=Sum('creatures__power')).order_by('-
wpower').values_list('id', flat=True)

The 'Creature'-Model has a foreign key to 'Wizard' with
related_name='creatures', and it has a 'power'-IntegerField.
However, I get a 'FieldError: Cannot resolve keyword 'wpower' into
field

The only way that works is:
[w.id for w in
Wizard.objects.filter(**filterargs).annotate(wpower=Sum('creatures__power')).order_by('-
wpower')]
or
[w.id for w in
Wizard.objects.filter(**filterargs).annotate(wpower=Sum('creatures__power')).order_by('-
wpower').iterator()]

However, this takes more from the db than what I actually want. Any
ideas how I can achieve what I want with minimal db-load?

[Andreas Pfrengle]

just pulling it up again...

[Marcos Moyano]

This should work without grabbing the entire table:

[x[0] for x in Wizard.objects.filter(**filterargs).annotate(wpower=Sum('creatures__power')).order_by('- wpower').values_list('id', 'wpower')]

Rgds,
Marcos

On Tue, Mar 22, 2011 at 5:25 PM, Andreas Pfrengle <a.pfr...@gmail.com> wrote:

just pulling it up again...

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[Andreas Pfrengle]

Thank you, it works! :-)