Fixed #1530 -- make count() respect distinct() on QuerySets. Create some

tests for this as well. Thanks to Adam Endicott for the original patch on which
this is based.



git-svn-id: http://code.djangoproject.com/svn/django/trunk@2902 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/db/models/query.py

@@ -182,7 +182,12 @@ class QuerySet(object):
         counter._select_related = False
         select, sql, params = counter._get_sql_clause()
         cursor = connection.cursor()
-        cursor.execute("SELECT COUNT(*)" + sql, params)
+        if self._distinct:
+            id_col = "%s.%s" % (backend.quote_name(self.model._meta.db_table),
+                    backend.quote_name(self.model._meta.pk.column))
+            cursor.execute("SELECT COUNT(DISTINCT(%s))" % id_col + sql, params)
+        else:
+            cursor.execute("SELECT COUNT(*)" + sql, params)
         return cursor.fetchone()[0]
 
     def get(self, *args, **kwargs):

tests/modeltests/many_to_many/models.py

@@ -82,6 +82,13 @@ API_TESTS = """
 >>> Article.objects.filter(publications__title__startswith="Science").distinct()
 [NASA uses Python]
 
+# The count() function respects distinct() as well.
+>>> Article.objects.filter(publications__title__startswith="Science").count()
+2
+
+>>> Article.objects.filter(publications__title__startswith="Science").distinct().count()
+1
+
 # Reverse m2m queries are supported (i.e., starting at the table that doesn't
 # have a ManyToManyField).
 >>> Publication.objects.filter(id__exact=1)

tests/modeltests/many_to_one/models.py

@@ -205,6 +205,12 @@ John Smith
 >>> Reporter.objects.filter(article__headline__startswith='This').distinct()
 [John Smith]
 
+# Counting in the opposite direction works in conjunction with distinct()
+>>> Reporter.objects.filter(article__headline__startswith='This').count()
+3
+>>> Reporter.objects.filter(article__headline__startswith='This').distinct().count()
+1
+
 # Queries can go round in circles.
 >>> Reporter.objects.filter(article__reporter__first_name__startswith='John')
 [John Smith, John Smith, John Smith, John Smith]