CODEWITHSUNDEEP
djangodjango-ormdjango-q
eric
eric

Reputation: 1020

Django ORM - select by multiple related objects and Q queries

Ok, we have three tables: Order, Product and OrderProduct. I want to find what Orders has some products, and I written the following function:

def get_orders_with_products(products):
    if len(products) < 1:
        raise Exception("at least one product expected")

    query = get_order_set_query(products[0])

    if len(procducts > 1):
        for product in products[1:]:
            query = query & get_order_set_query(product)

    return Order.objects.filter(query)

def get_order_set_query(product):
    product_orders = OrderProduct.objects \
        .values_list('order_id', flat=True)\
        .filter(product=product)
    return Q(id__in=set(product_orders))

This code would result in a sql query like the following:

select * from Orders
where id in [1, 2, 3]
and id in [2, 3, 4]

Is there any way to make Django's ORM write the following query?

select * from Orders
where id in (select order_id from OrderProduct where product_id = 1)
and id in (select order_id from OrderProduct where product_id = 2)

Any suggestions to do this better?

Upvotes: 0

Views: 667

Answers (1)

Odif Yltsaeb
Odif Yltsaeb

Reputation: 5656

Yes.

from django.db.models import Q

queryset = Order.objects.filter(Q(order_id = [1, 2, 3]) & Q(order_id = [2, 3, 4]))

You could replace the lists with something like 

[id[0] for id in OrderProduct.objects.filter(product_id = 1).values_list('id')]

Alan

Upvotes: 0

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