diff git a/django/db/models/aggregates.py b/django/db/models/aggregates.py
index 9db0910..e9c4213 100644
a

b

class Aggregate(object): 
6  6  """ 
7  7  Default Aggregate definition. 
8  8  """ 
9   def __init__(self, name, lookup, **extra): 
10   self.name = name 
 9  def __init__(self, lookup, **extra): 
11  10  self.lookup = lookup 
12  11  self.extra = extra 
13  12  
… 
… 
class Aggregate(object): 
19  18  return getattr(engine, self.name)(col, source, is_summary, **self.extra) 
20  19  
21  20  class Max(Aggregate): 
22   def __init__(self, lookup): 
23   super(Max, self).__init__('Max', lookup) 
24   
 21  name = 'Max' 
 22  
25  23  class Min(Aggregate): 
26   def __init__(self, lookup): 
27   super(Min, self).__init__('Min', lookup) 
 24  name = 'Min' 
28  25  
29  26  class Avg(Aggregate): 
30   def __init__(self, lookup): 
31   super(Avg, self).__init__('Avg', lookup) 
 27  name = 'Avg' 
32  28  
33  29  class Sum(Aggregate): 
34   def __init__(self, lookup): 
35   super(Sum, self).__init__('Sum', lookup) 
 30  name = 'Sum' 
36  31  
37  32  class Count(Aggregate): 
 33  name = 'Count' 
 34  
38  35  def __init__(self, lookup, distinct=False): 
39   super(Count, self).__init__('Count', lookup, distinct=distinct) 
 36  super(Count, self).__init__(lookup, distinct=distinct) 
diff git a/django/db/models/sql/aggregates.py b/django/db/models/sql/aggregates.py
index f15e80f..f00634c 100644
a

b

class Aggregate(object): 
11  11  is_computed = False 
12  12  sql_template = '%(function)s(%(field)s)' 
13  13  
14   def __init__(self, function, col, source=None, is_summary=False, **extra): 
15   self.sql_function = function 
 14  def __init__(self, col, source=None, is_summary=False, **extra): 
16  15  self.col = col 
17  16  self.is_summary = is_summary 
18  17  self.extra = extra 
… 
… 
class Aggregate(object): 
50  49  
51  50  
52  51  class Max(Aggregate): 
53   def __init__(self, col, source=None, is_summary=False): 
54   super(Max, self).__init__('MAX', col, source, is_summary) 
55   
 52  sql_function = 'MAX' 
 53  
56  54  class Min(Aggregate): 
57   def __init__(self, col, source=None, is_summary=False): 
58   super(Min, self).__init__('MIN', col, source, is_summary) 
 55  sql_function = 'MIN' 
59  56  
60  57  class Avg(Aggregate): 
61  58  is_computed = True 
62   
63   def __init__(self, col, source=None, is_summary=False): 
64   super(Avg, self).__init__('AVG', col, source, is_summary) 
 59  sql_function = 'AVG' 
65  60  
66  61  class Sum(Aggregate): 
67   def __init__(self, col, source=None, is_summary=False): 
68   super(Sum, self).__init__('SUM', col, source, is_summary) 
 62  sql_function = 'SUM' 
69  63  
70  64  class Count(Aggregate): 
71  65  is_ordinal = True 
 66  sql_function = 'COUNT' 
72  67  sql_template = '%(function)s(%(distinct)s%(field)s)' 
73  68  
74  69  def __init__(self, col, source=None, is_summary=False, distinct=False): 
75   super(Count, self).__init__('COUNT', col, source, is_summary, distinct=distinct and 'DISTINCT ' or '') 
 70  super(Count, self).__init__(col, source, is_summary, distinct=distinct and 'DISTINCT ' or '') 