On Fri, Oct 2, 2009 at 11:49 AM, Jumpfroggy <rocketmonk...@gmail.com> wrote:
>
> I have a model with a field, and I wanted to pull all the unique
> values of that field. So I do this:
>
> distinct_values = Model.objects.values('some_column').distinct()
> print 'distinct_values.count()', distinct_values.count()
> print 'len(distinct_values)', len(distinct_values)
>
> Which gives:
>
> distinct_values.count() 4
> len(distinct_values) 137
>
>
I suspect you have an ordering specified for the Model that is pulling in
more columns when the query set is evaluated. (I do not know whether it is
a bug that these are not pulled in when you just call count().) The need to
be careful with disctint() and ordering is noted here:
http://docs.djangoproject.com/en/dev/ref/models/querysets/#distinct
The fix is to ensure default ordering does not interfere with distinct:
distinct_values = Model.objects.order_by().values('some_column').distinct()
Karen
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