gistfile1.py

    @classmethod
    def get_all_from_assignment_id(cls, session, assignment_id, \
            deleted=False, start=0, count=0):
        with transaction.manager:
            posts_query = session.query(
                Posts.post_id,
                Posts.assignment_id,
                Posts.client_id,
                Posts.post_datetime,
                Posts.deleted,
                Posts.lat,
                Posts.lng,
                MediaObjects.media_object_id,
                MediaObjects.media_id,
                MediaObjects.file_name,
                MediaObjects.caption,
                MediaObjects.media_text,
                MediaTypes.name,
                MediaTypes.description,
                Clients.verified,
                Clients.client_id,
                Languages.language_code,
                Languages.name,
            ).join(
                PostMediaObjects,
            ).join(
                MediaObjects,
            ).join(
                MediaTypes,
            ).join(
                Clients,
                Clients.client_id == \
                    Posts.client_id,
            ).join(
                Languages,
            ).filter(
                Posts.assignment_id == assignment_id,
                Posts.deleted == deleted,
            ).order_by(
                 desc(Posts.post_datetime),
            ).group_by(
                 Posts.post_id,
            )
            total_post_count = posts_query.count()
            if start == 0 and count == 0:
                posts = posts_query.all()
            else:
                posts = posts_query.slice(start, start+count)
        return posts, total_post_count
        
 SELECT Count(*) AS count_1
FROM   (
                SELECT   posts.post_id                AS posts_post_id,
                         posts.assignment_id          AS posts_assignment_id,
                         posts.client_id              AS posts_client_id,
                         posts.post_datetime          AS posts_post_datetime,
                         posts.deleted                AS posts_deleted,
                         posts.lat                    AS posts_lat,
                         posts.lng                    AS posts_lng,
                         mediaobjects.media_object_id AS mediaobjects_media_object_id,
                         mediaobjects.media_id        AS mediaobjects_media_id,
                         mediaobjects.file_name       AS mediaobjects_file_name,
                         mediaobjects.caption         AS mediaobjects_caption,
                         mediaobjects.media_text      AS mediaobjects_media_text,
                         mediatypes.NAME              AS mediatypes_name,
                         mediatypes.description       AS mediatypes_description,
                         clients.verified             AS clients_verified,
                         clients.client_id            AS clients_client_id,
                         languages.language_code      AS languages_language_code,
                         languages.NAME               AS languages_name
                FROM     posts
                JOIN     postmediaobjects
                ON       posts.post_id = postmediaobjects.post_id
                JOIN     mediaobjects
                ON       mediaobjects.media_object_id = postmediaobjects.media_object_id
                JOIN     mediatypes
                ON       mediatypes.media_type_id = mediaobjects.media_type_id
                JOIN     clients
                ON       clients.client_id = posts.client_id
                JOIN     languages
                ON       languages.language_id = posts.language_id
                WHERE    posts.assignment_id = %(assignment_id_1)s
                AND      posts.deleted = false
                GROUP BY posts.post_id
                ORDER BY posts.post_datetime DESC) AS anon_1 

That produces this error:
 
2015-03-03 09:40:07,150 ERROR [waitress][Dummy-2] Exception when serving /admin/get_assignment_responses.json
Traceback (most recent call last):
  File "<redacted>.virtualenvs/yellr-server/local/lib/python2.7/site-packages/waitress-0.8.9-py2.7.egg/waitress/channel.py", line 337, in service
    task.service()
  File "<redacted>.virtualenvs/yellr-server/local/lib/python2.7/site-packages/waitress-0.8.9-py2.7.egg/waitress/task.py", line 173, in service
    self.execute()
  File "<redacted>.virtualenvs/yellr-server/local/lib/python2.7/site-packages/waitress-0.8.9-py2.7.egg/waitress/task.py", line 392, in execute
    app_iter = self.channel.server.application(env, start_response)
  File "<redacted>.virtualenvs/yellr-server/local/lib/python2.7/site-packages/pyramid-1.5.2-py2.7.egg/pyramid/router.py", line 242, in __call__
    response = self.invoke_subrequest(request, use_tweens=True)
  File "<redacted>.virtualenvs/yellr-server/local/lib/python2.7/site-packages/pyramid-1.5.2-py2.7.egg/pyramid/router.py", line 217, in invoke_subrequest
    response = handle_request(request)
  File "<redacted>.virtualenvs/yellr-server/local/lib/python2.7/site-packages/pyramid-1.5.2-py2.7.egg/pyramid/tweens.py", line 21, in excview_tween
    response = handler(request)
  File "<redacted>.virtualenvs/yellr-server/local/lib/python2.7/site-packages/pyramid_tm-0.8-py2.7.egg/pyramid_tm/__init__.py", line 92, in tm_tween
    reraise(*exc_info)
  File "<redacted>.virtualenvs/yellr-server/local/lib/python2.7/site-packages/pyramid_tm-0.8-py2.7.egg/pyramid_tm/__init__.py", line 73, in tm_tween
    response = handler(request)
  File "<redacted>.virtualenvs/yellr-server/local/lib/python2.7/site-packages/pyramid-1.5.2-py2.7.egg/pyramid/router.py", line 163, in handle_request
    response = view_callable(context, request)
  File "<redacted>.virtualenvs/yellr-server/local/lib/python2.7/site-packages/pyramid-1.5.2-py2.7.egg/pyramid/config/views.py", line 385, in viewresult_to_response
    result = view(context, request)
  File "<redacted>.virtualenvs/yellr-server/local/lib/python2.7/site-packages/pyramid-1.5.2-py2.7.egg/pyramid/config/views.py", line 501, in _requestonly_view
    response = view(request)
  File "<redacted>/yellr-server/yellr-serv/yellrserv/admin_views.py", line 896, in admin_get_assignment_responses
    count = count,
  File "<redacted>/yellr-server/yellr-serv/yellrserv/models.py", line 1257, in get_all_from_assignment_id
    total_post_count = posts_query.count()
  File "<redacted>.virtualenvs/yellr-server/local/lib/python2.7/site-packages/SQLAlchemy-0.9.8-py2.7-linux-x86_64.egg/sqlalchemy/orm/query.py", line 2640, in count
    return self.from_self(col).scalar()
  File "<redacted>.virtualenvs/yellr-server/local/lib/python2.7/site-packages/SQLAlchemy-0.9.8-py2.7-linux-x86_64.egg/sqlalchemy/orm/query.py", line 2426, in scalar
    ret = self.one()
  File "<redacted>.virtualenvs/yellr-server/local/lib/python2.7/site-packages/SQLAlchemy-0.9.8-py2.7-linux-x86_64.egg/sqlalchemy/orm/query.py", line 2395, in one
    ret = list(self)
  File "<redacted>.virtualenvs/yellr-server/local/lib/python2.7/site-packages/SQLAlchemy-0.9.8-py2.7-linux-x86_64.egg/sqlalchemy/orm/query.py", line 2438, in __iter__
    return self._execute_and_instances(context)
  File "<redacted>.virtualenvs/yellr-server/local/lib/python2.7/site-packages/SQLAlchemy-0.9.8-py2.7-linux-x86_64.egg/sqlalchemy/orm/query.py", line 2453, in _execute_and_instances
    result = conn.execute(querycontext.statement, self._params)
  File "<redacted>.virtualenvs/yellr-server/local/lib/python2.7/site-packages/SQLAlchemy-0.9.8-py2.7-linux-x86_64.egg/sqlalchemy/engine/base.py", line 729, in execute
    return meth(self, multiparams, params)
  File "<redacted>.virtualenvs/yellr-server/local/lib/python2.7/site-packages/SQLAlchemy-0.9.8-py2.7-linux-x86_64.egg/sqlalchemy/sql/elements.py", line 322, in _execute_on_connection
    return connection._execute_clauseelement(self, multiparams, params)
  File "<redacted>.virtualenvs/yellr-server/local/lib/python2.7/site-packages/SQLAlchemy-0.9.8-py2.7-linux-x86_64.egg/sqlalchemy/engine/base.py", line 826, in _execute_clauseelement
    compiled_sql, distilled_params
  File "<redacted>.virtualenvs/yellr-server/local/lib/python2.7/site-packages/SQLAlchemy-0.9.8-py2.7-linux-x86_64.egg/sqlalchemy/engine/base.py", line 958, in _execute_context
    context)
  File "<redacted>.virtualenvs/yellr-server/local/lib/python2.7/site-packages/SQLAlchemy-0.9.8-py2.7-linux-x86_64.egg/sqlalchemy/engine/base.py", line 1159, in _handle_dbapi_exception
    exc_info
  File "<redacted>.virtualenvs/yellr-server/local/lib/python2.7/site-packages/SQLAlchemy-0.9.8-py2.7-linux-x86_64.egg/sqlalchemy/util/compat.py", line 199, in raise_from_cause
    reraise(type(exception), exception, tb=exc_tb)
  File "<redacted>.virtualenvs/yellr-server/local/lib/python2.7/site-packages/SQLAlchemy-0.9.8-py2.7-linux-x86_64.egg/sqlalchemy/engine/base.py", line 951, in _execute_context
    context)
  File "<redacted>.virtualenvs/yellr-server/local/lib/python2.7/site-packages/SQLAlchemy-0.9.8-py2.7-linux-x86_64.egg/sqlalchemy/engine/default.py", line 436, in do_execute
    cursor.execute(statement, parameters)
ProgrammingError: (ProgrammingError) column "mediaobjects.media_object_id" must appear in the GROUP BY clause or be used in an aggregate function
LINE 2: ..., posts.lat AS posts_lat, posts.lng AS posts_lng, mediaobjec...