I have two queries:
Proyecto.objects.filter().order_by('tipo_proyecto')
Proyecto.objects.values('tipo_proyecto').annotate(total=Sum('techo_presupuestario'))
How can I make this in only one query? I want that the first query contains an annotate data that represents all sums of techo_presupuestario, depending on your tipo_proyecto. Is this posible?
If I understand you correct, you'd like to add a conditionally aggregated sum over one field to each object, so you get each object with a sum fitting to its tipo_proyecto. Right? I don't know, if this makes sense, but it could be done anyway using Subquery:
from django.db.models import Sum, Subquery, OuterRef
sq = Subquery(Proyecto.objects.filter(tipo_proyecto=OuterRef("tipo_proyecto")).values("tipo_proyecto").annotate(techoSum=Sum("techo_presupuestario")).values("techoSum"))
Proyecto.objects.all().annotate(tipoTechoSum = sq).order_by('tipo_proyecto')
Nonetheless, I wouldn't recommend this, as it puts some heavy load on your database. (In MySQL there will be an nested SELECT statement referring to the same table, which might be pretty unpleasant depending on the table's size.)
I'd say the better approach is to "collect" your aggregated sums separately and add the values to the model objects in your code.
