queryset-refactor: Made qs.dates(...).count() work.

This involved a slight change in the SQL for .dates() which appears to be
correct and passes all the tests, but may have some side-effect I don't know
about.

Refs #6203.


git-svn-id: http://code.djangoproject.com/svn/django/branches/queryset-refactor@6959 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/db/models/sql/datastructures.py

@@ -50,12 +50,14 @@ class Count(Aggregate):
             quote_func = lambda x: x
         if isinstance(self.col, (list, tuple)):
             col = ('%s.%s' % tuple([quote_func(c) for c in self.col]))
+        elif hasattr(self.col, 'as_sql'):
+            col = self.col.as_sql(quote_func)
         else:
             col = self.col
         if self.distinct:
             return 'COUNT(DISTINCT %s)' % col
         else:
-            return 'COUNT(%s)' % self.col
+            return 'COUNT(%s)' % col
 
 class Date(object):
     """

django/db/models/sql/query.py

@@ -193,6 +193,8 @@ class Query(object):
         if obj.distinct and len(obj.select) > 1:
             obj = self.clone(CountQuery, _query=obj, where=WhereNode(),
                     distinct=False)
+            obj.select = []
+            obj.extra_select = SortedDict()
         obj.add_count_column()
         data = obj.execute_sql(SINGLE)
         if not data:
@@ -1008,13 +1010,18 @@ class Query(object):
 
     def add_count_column(self):
         """
-        Converts the query to do count(*) or count(distinct(pk)) in order to
+        Converts the query to do count(...) or count(distinct(pk)) in order to
         get its size.
         """
         # TODO: When group_by support is added, this needs to be adjusted so
         # that it doesn't totally overwrite the select list.
         if not self.distinct:
-            select = Count()
+            if not self.select:
+                select = Count()
+            else:
+                assert len(self.select) == 1, \
+                        "Cannot add count col with multiple cols in 'select': %r" % self.select
+                select = Count(self.select[0])
         else:
             opts = self.model._meta
             if not self.select:
@@ -1229,11 +1236,8 @@ class DateQuery(Query):
         select = Date((alias, column), lookup_type,
                 self.connection.ops.date_trunc_sql)
         self.select = [select]
+        self.distinct = True
         self.order_by = order == 'ASC' and [1] or [-1]
-        if self.connection.features.allows_group_by_ordinal:
-            self.group_by = [1]
-        else:
-            self.group_by = [select]
 
 class CountQuery(Query):
     """

tests/regressiontests/queries/models.py

@@ -2,6 +2,8 @@
 Various complex queries that have been problematic in the past.
 """
 
+import datetime
+
 from django.db import models
 from django.db.models.query import Q
 
@@ -42,6 +44,7 @@ class Author(models.Model):
 
 class Item(models.Model):
     name = models.CharField(max_length=10)
+    created = models.DateTimeField()
     tags = models.ManyToManyField(Tag, blank=True, null=True)
     creator = models.ForeignKey(Author)
     note = models.ForeignKey(Note)
@@ -129,15 +132,19 @@ by 'info'. Helps detect some problems later.
 >>> a4 = Author(name='a4', num=4004, extra=e2)
 >>> a4.save()
 
->>> i1 = Item(name='one', creator=a1, note=n3)
+>>> time1 = datetime.datetime(2007, 12, 19, 22, 25, 0)
+>>> time2 = datetime.datetime(2007, 12, 19, 21, 0, 0)
+>>> time3 = datetime.datetime(2007, 12, 20, 22, 25, 0)
+>>> time4 = datetime.datetime(2007, 12, 20, 21, 0, 0)
+>>> i1 = Item(name='one', created=time1, creator=a1, note=n3)
 >>> i1.save()
 >>> i1.tags = [t1, t2]
->>> i2 = Item(name='two', creator=a2, note=n2)
+>>> i2 = Item(name='two', created=time2, creator=a2, note=n2)
 >>> i2.save()
 >>> i2.tags = [t1, t3]
->>> i3 = Item(name='three', creator=a2, note=n3)
+>>> i3 = Item(name='three', created=time3, creator=a2, note=n3)
 >>> i3.save()
->>> i4 = Item(name='four', creator=a4, note=n3)
+>>> i4 = Item(name='four', created=time4, creator=a4, note=n3)
 >>> i4.save()
 >>> i4.tags = [t4]
 
@@ -244,7 +251,7 @@ Bug #1878, #2939
 
 # Create something with a duplicate 'name' so that we can test multi-column
 # cases (which require some tricky SQL transformations under the covers).
->>> xx = Item(name='four', creator=a2, note=n1)
+>>> xx = Item(name='four', created=time1, creator=a2, note=n1)
 >>> xx.save()
 >>> Item.objects.exclude(name='two').values('creator', 'name').distinct().count()
 4
@@ -471,5 +478,15 @@ Multiple filter statements are joined using "AND" all the time.
 [<Author: a1>]
 >>> Author.objects.filter(Q(extra__note=n1)|Q(item__note=n3)).filter(id=a1.id)
 [<Author: a1>]
+
+Bug #6203
+>>> Item.objects.count()
+4
+>>> Item.objects.dates('created', 'month').count()
+1
+>>> Item.objects.dates('created', 'day').count()
+2
+>>> len(Item.objects.dates('created', 'day'))
+2
 """}