Values_list with distinct return duplicate values

[jonasnockert]

I'm using Django 1.3 with the following model (and as far as I can tell the generated sqlite3 schema looks okay as well):

class Article(Model):
    product_number = PositiveIntegerField(_("Product number"), db_index=True)
    product_variant = PositiveIntegerField(_("Variant"), db_index=True)
    ...
    class Meta:
        unique_together = (('product_number', 'product_variant'),)
        ordering = ['-date_added']

I'm making the following query which returns duplicate results:

>>> Article.objects.filter(product_number=99668).values_list('product_number', flat=True).distinct()
[99668, 99668]

It looks like a bug from here but I'm also a bit sceptical since other people seem to be using this query construct successfully.

Thanks!

[Ramiro Morales]

I suspect is is because the (default, implicit) ordering Article model queries have and/or the unique_together condition. You are seeing duplicate results because .distinct() is acting on all the columns included in the low level SQL query.

Take a look at:

• The note in the ​distinct() method and
• the suggestion in the last paragraph of the ​values() method (using .unique().values_list(...) if possible)

[jeroenp@…]

See ​https://docs.djangoproject.com/en/1.3/ref/models/querysets/#django.db.models.query.QuerySet.distinct

Add an order_by('product_number')

[Pavel White]

You can use .sorted_by() for clear sorted meta oredering.

Ex:

>>> Article.objects.filter(product_number=99668).sorted_by().values_list('product_number', flat=True).distinct()
[99668]