Question

I have the following data structure: FruitObject with fields FruitType and FruitColor. On the other hand I have FruitOffer (which is input by user). It has same fields as FruitObject and is being input by user (some kind of demand-support pairing system; we input FruitObjects and user input FruitOffers; the task is to pair them and see what a user has to offer us – to select only those FruitObjects that are equal to FruitOffers for specific user).

So logically I’ve used __in selection to get needed data:

select = FruitObject.objects.filter(FruitType__in=FruitOffer.objects.filter(user=request.user).values("FruitType"))

Now comes the hard part for me – I need to add FruitColor to the select and get many-to-many select that fulfills both conditions (for each fruitObject get offerObject that is BOTH of TYPE and COLOR)

select = FruitObject.objects.filter(FruitType__in=FruitOffer.objects.filter(user=request.user).values("FruitType"), FruitColor__in=FruitOffer.objects.filter(user=request.user).values("FruitColor"))

But comma is operating more like OR in this case and returns me all values that are of specific Type or of specific Color.

How do add AND condition to __in select? If i’d like to add more conditions (like price or taste), will it be done in same way? Thanks in advance.

Answer 1

The hard way.

FruitObject.objects.filter(reduce(operator.or_, (Q(FruitColor=color, FruitType=type) for (color, type) in FruitOffer.objects.filter(user=request.user).values_list('FruitColor', 'FruitType'))))