python - Exclude documents from query with duplicate fields value -

could me? how using mongoengine exclude queryset documents fields have same value?

suppose, have model:

class a(document):     = intfield()     b = intfield()     c = intfield()

documents in db:

{'a':1, 'b':1, 'c':1 } {'a':1, 'b':1, 'c':2 } {'a':1, 'b':2, 'c':1 }

query: a.objects() documents

how can query documents:

{'a':1, 'b':1, 'c':1 } {'a':1, 'b':2, 'c':1 }

it should exclude documents, if queryset has document same values 'a' , 'b' together. such document should included in queryset once.

one way use aggregate, this:

pipe = {"$group": {"_id": {"a": "$a", "b": "$b", "c": "$c"}}} a.objects.aggregate(pipeline=pipe)

another way query fields excluding _id, , calculate unique records out results.

UV code