Here's my database query:

```
results = Attachments.objects.filter(currency='current').annotate(num_attachments=Count('article_id')).order_by("num_attachments").distinct('article_id')

```

The query broken down as follows (as I understand it):

* First filter is current Attachments that are "current".
* Then to count the number of those Attachments with a certain 'article\_id'.
* Then to annotate each Attachment with the number of Attachment with the number of those that have article\_id in common.
* Then to rank based on the number of attachments.
* Then, paring down the list with distinct, so that there's one Attachment object for each article\_id value.

I am running this on PostgreSQL, so according to the Django [docs](https://docs.djangoproject.com/en/dev/ref/models/querysets/), I'm fine to run distinct() based on a field.

There is no error when I execute the query, but when I try to iterate or even print the results the following error is thrown by Django debug:

```
NotImplementedError at /function/
annotate() + distinct(fields) not implemented.

```

The more detailed traceback from the interactive prompt is:

```
  File "<console>", line 1, in <module>
  File "/Users/Pat/.virtualenvs/envsp/lib/python2.7/site-packages/django/db/models/query.py", line 118, in _result_iter
    self._fill_cache()
  File "/Users/Pat/.virtualenvs/envsp/lib/python2.7/site-packages/django/db/models/query.py", line 875, in _fill_cache
    self._result_cache.append(self._iter.next())
  File "/Users/Pat/.virtualenvs/envsp/lib/python2.7/site-packages/django/db/models/query.py", line 291, in iterator
    for row in compiler.results_iter():
  File "/Users/Pat/.virtualenvs/envsp/lib/python2.7/site-packages/django/db/models/sql/compiler.py", line 763, in results_iter
    for rows in self.execute_sql(MULTI):
  File "/Users/Pat/.virtualenvs/envsp/lib/python2.7/site-packages/django/db/models/sql/compiler.py", line 808, in execute_sql
    sql, params = self.as_sql()
  File "/Users/Pat/.virtualenvs/envsp/lib/python2.7/site-packages/django/db/models/sql/compiler.py", line 107, in as_sql
    "annotate() + distinct(fields) not implemented.")
NotImplementedError: annotate() + distinct(fields) not implemented.

```

Anyone know what's going on here?