Django concatenate two querysets for same model

Question

I have a list of Products, each belonging to a different Distributor.

I need to display a form for each of those products and their corresponding distributor. I can do so with this code:

form_products = ProductFormSet(
    queryset = Product.objects.filter(product__id=product_id)
)

The problem is that I need to display the form with the product belonging to a particular Distributor named "FirstDistributor" first in the page.

I tried to do so with the following code using the | operator between the querysets:

form_products = ProductFormSet(
    queryset=(
        Product.objects.filter(
            product__id=product_id, 
            distributor__name='FirstDistributor') | 
        Product.objects.filter(
            product__id=product_id
        ).exclude(distributor__name='FirstDistributor')
    )
)

But the forms are still displayed in the same order. How can I concatenate those two querysets into one, while keeping the same order?

q1 = Product.objects.filter(product__id=product_id,
    distributor__name='FirstDistributor')

and

q2 = Product.objects.filter(product__id=product_id
    ).exclude(distributor__name='FirstDistributor')

Thanks!

The Queryset class implements the iterator interface so it can be used as that, hence the itertools.chain method can be used to combine multiple querysets of the the same model together — Fanis Despoudis
– Fanis Despoudis, Commented May 7, 2015 at 18:32

Community · Accepted Answer · 2017-05-23 12:32:10Z

3

You can try to do it like here:

https://stackoverflow.com/a/2176471/4971083

It's the solution for ordering your records by specific value in Django. You could order your records by distributor_name = 'FirstDistributor'

p= Product.objects.filter(product__id=product_id).extra(
select={'is_top': " distributor__name='FirstDistributor'"})
p = p.extra(order_by = ['-is_top'])

edited May 23, 2017 at 12:32

CommunityBot

11 silver badge

answered Jun 6, 2015 at 17:43

koala

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Comments

Community · Accepted Answer · 2017-05-23 11:46:21Z

1

You can use itertools to combine the two:

from itertools import chain
result_list = list(chain(page_list, article_list, post_list))

Source: https://stackoverflow.com/a/434755/3279262

edited May 23, 2017 at 11:46

CommunityBot

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answered May 7, 2015 at 15:40

Jorick Spitzen

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