diff --git a/activerecord/lib/active_record/calculations.rb b/activerecord/lib/active_record/calculations.rb
index 727f4c1dc620a636713a8db4e89e85a61be59148..4a88c43dfff640b980068a15bcbfa811edda8f20 100644
--- a/activerecord/lib/active_record/calculations.rb
+++ b/activerecord/lib/active_record/calculations.rb
@@ -197,6 +197,8 @@ def construct_calculation_sql(operation, column_name, options) #:nodoc:
           sql << ", #{options[:group_field]} AS #{options[:group_alias]}" if options[:group]
           if options[:from]
             sql << " FROM #{options[:from]} "
+          elsif scope && scope[:from]
+            sql << " FROM #{scope[:from]} "
           else
             sql << " FROM (SELECT #{distinct}#{column_name}" if use_workaround
             sql << " FROM #{connection.quote_table_name(table_name)} "
diff --git a/activerecord/test/cases/calculations_test.rb b/activerecord/test/cases/calculations_test.rb
index 24bc4f71ce41287dfb38de2c05cf229a6859a537..c2e02763f617ff13a553a6884c91d99157837987 100644
--- a/activerecord/test/cases/calculations_test.rb
+++ b/activerecord/test/cases/calculations_test.rb
@@ -2,6 +2,8 @@
 require 'models/company'
 require 'models/topic'
 require 'models/edge'
+require 'models/club'
+require 'models/organization'
 
 Company.has_many :accounts
 
@@ -223,6 +225,10 @@ def test_should_sum_scoped_field
     assert_equal 15, companies(:rails_core).companies.sum(:id)
   end
 
+  def test_should_sum_scoped_field_with_from
+    assert_equal Club.count, Organization.clubs.count
+  end
+
   def test_should_sum_scoped_field_with_conditions
     assert_equal 8,  companies(:rails_core).companies.sum(:id, :conditions => 'id > 7')
   end
diff --git a/activerecord/test/models/organization.rb b/activerecord/test/models/organization.rb
index d79d5037c805320e19ef64b4575157f9571356b1..c85726169eeabba68728b5c770ca26559aa2d632 100644
--- a/activerecord/test/models/organization.rb
+++ b/activerecord/test/models/organization.rb
@@ -1,4 +1,6 @@
 class Organization < ActiveRecord::Base
   has_many :member_details
   has_many :members, :through => :member_details
+
+  named_scope :clubs, { :from => 'clubs' }
 end
\ No newline at end of file