On 22 mar, 11:08, Kevin Renskers <i...@bolhoed.net> wrote:
> Hi,
>
> I am using a combination of the only() and distinct() functions on a
> model to get the unique values of one column. Sadly, the only()
> function also includes the primary key (even though I only give one
> column name), which has the effect that all rows are seen as unique.
only() is only (no pun) a complement to defer() - it still loads the
Model instances, so you'll indeed have the primary key included.
The method you want is values_list:
>> results = YourModel.objects.values_list('power_meter', flat=True).distinct()
> This is the result I want:
> power_meter
> 1
> 2
> 3
>
> This is the result I get:
> id power_meter
> 80 1
> 81 1
> 82 1
> 83 2
> 84 2
> 85 3
> 86 3
>
> So I am wondering why the primary key is included in the query, even
> though I used only('power_meter') in my query.
cf above. Querysets default behaviour is to yield Model instances -
not raw data -, and Model instances neeed to have their primary key
loaded to work correctly. If you want raw data, use either values() or
values_list()
HTH
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