I have a large inventory of vehicles, and there are a lot of duplicates that are only unique by a stock number. I am trying to query for a list of all vehicles, but only want one vehicle for each model number, ignoring it's stock number field.
V1.stock_no = 15393
V2.stock_no = 15394
V1.model_no = 98874
V2.model_no = 98874
So when doing a query in Django, I only want one instance of each object with that model no. I read this Stack Overflow question Select DISTINCT individual columns in django?, but
q = ProductOrder.objects.values('Category').distinct()
just returns a distinct list of model numbers, and not the object instance, and
Productorder.objects.all().distinct('category')
made available since Django 1.4, only works with PostgreSQL, and not SQLite3.
Is there any way to do this with SQLite, without having some contrived for loop to get it done ?
This is one potential solution
q = ProductOrder.objects.filter(
id__in=ProductOrder.objects.values('Category')
.distinct()
.values_list('id', flat=True))
Edit: alternatively, you can try
q1 = ProductOrder.objects.values('Category')
.distinct()
.annotate(x=Max('id'))
q2 = ProductOrder.objects.filter(
id__in=[i["x"] for i in q1])
I realize this is not ideal however due to having to loop.