[Django]-How to check whether all the values of a database field are same using django queries

Can propose You count lines using filter

if Product.objects.all().count() == Product.objects.filter(price=price).count():
    pass

or use distinct

if Product.objects.all().products.distinct('price').count() == 1:
    pass

Note that this example works correctly on Portgres only.

Also You can Use annotate to calculate count I think

if Product.objects.all().values('price').annotate(Count('price')).count() == 1:
    pass