Merge pull request #77 from edx/dsjen/aggregate-problem-submissions

Updated problem endpoint to return problem submissions.

analytics_data_api/v0/tests/views/test_courses.py

@@ -620,8 +620,8 @@ class CourseProblemsListViewTests(DemoCourseMixin, TestCaseWithAuthentication):
         expected = [
             {
                 'module_id': module_id,
-                'total_submissions': 300,
-                'correct_submissions': 100,
+                'total_submissions': 150,
+                'correct_submissions': 50,
                 'part_ids': [o1.part_id, o3.part_id],
                 'created': alt_created.strftime(settings.DATETIME_FORMAT)
             },

analytics_data_api/v0/views/courses.py

@@ -632,11 +632,14 @@ class ProblemsListView(BaseCourseView):
     allow_empty = False
 
     def get_queryset(self):
+        # last_response_count is the number of submissions for the problem part and must
+        # be divided by the number of problem parts to get the problem submission rather
+        # than the problem *part* submissions
         aggregation_query = """
 SELECT
     module_id,
-    SUM(last_response_count) AS total_submissions,
-    SUM(CASE WHEN correct=1 THEN last_response_count ELSE 0 END) AS correct_submissions,
+    SUM(last_response_count)/COUNT(DISTINCT part_id) AS total_submissions,
+    SUM(CASE WHEN correct=1 THEN last_response_count ELSE 0 END)/COUNT(DISTINCT part_id) AS correct_submissions,
     GROUP_CONCAT(DISTINCT part_id) AS part_ids,
     MAX(created) AS created
 FROM answer_distribution