Fixes issue where SQL fragments prevented type casting based on column type.

2 files changed, 6 insertions, 8 deletions

diff --git a/activerecord/lib/active_record/relation/calculations.rb b/activerecord/lib/active_record/relation/calculations.rb
index aa2f325f74..862009b1ba 100644
--- a/activerecord/lib/active_record/relation/calculations.rb
+++ b/activerecord/lib/active_record/relation/calculations.rb
@@ -147,17 +147,12 @@ module ActiveRecord
       end
 
       result = klass.connection.select_all(select(column_name).arel, nil, bind_values)
-      types  = result.column_types.merge klass.column_types
-      column = types[key]
+      column = klass.column_types[key] || result.column_types.values.first
 
       result.map do |attributes|
         raise ArgumentError, "Pluck expects to select just one attribute: #{attributes.inspect}" unless attributes.one?
-        value = klass.initialize_attributes(attributes).first[1]
-        if column
-          column.type_cast value
-        else
-          value
-        end
+        value = klass.initialize_attributes(attributes).values.first
+        column ? column.type_cast(value) : value
       end
     end
 
diff --git a/activerecord/test/cases/calculations_test.rb b/activerecord/test/cases/calculations_test.rb
index c9a70bae77..f8bd11e3d0 100644
--- a/activerecord/test/cases/calculations_test.rb
+++ b/activerecord/test/cases/calculations_test.rb
@@ -468,6 +468,9 @@ class CalculationsTest < ActiveRecord::TestCase
 
   def test_pluck_with_selection_clause
     assert_equal [50, 53, 55, 60], Account.pluck('DISTINCT credit_limit').sort
+    assert_equal [50, 53, 55, 60], Account.pluck('DISTINCT accounts.credit_limit').sort
+    assert_equal [50, 53, 55, 60], Account.pluck('DISTINCT(credit_limit)').sort
+    assert_equal [50 + 53 + 55 + 60], Account.pluck('SUM(DISTINCT(credit_limit))')
   end
 
   def test_pluck_expects_a_single_selection