ActiveRecord::Calculations#pluck accepts multiple columns

activerecord/lib/active_record/relation/calculations.rb

@@ -127,6 +127,12 @@ def calculate(operation, column_name, options = {})
     #   # SELECT people.id FROM people
     #   # => [1, 2, 3]
     #
+    #   Person.pluck([:id, :name]) 
+    #   # SELECT people.id, people.name FROM people
+    #
+    #   Person.pluck(:id, :name) 
+    #   # SELECT people.id, people.name FROM people
+    #
     #   Person.uniq.pluck(:role)
     #   # SELECT DISTINCT role FROM people
     #   # => ['admin', 'member', 'guest']
@@ -139,11 +145,13 @@ def calculate(operation, column_name, options = {})
     #   # SELECT DATEDIFF(updated_at, created_at) FROM people
     #   # => ['0', '27761', '173']
     #
-    def pluck(column_name)
-      if column_name.is_a?(Symbol) && column_names.include?(column_name.to_s)
-        column_name = "#{table_name}.#{column_name}"
+    def pluck(*column_name)
+      if column_name.size == 1 && column_name.first.is_a?(Symbol) && column_names.include?(column_name.first.to_s)
+        column_name = "#{table_name}.#{column_name.first}"
+      elsif column_name.is_a?(Array)
+        column_name.flatten!
       end
-
+      
       result = klass.connection.select_all(select(column_name).arel, nil, bind_values)
 
       key    = result.columns.first
@@ -154,11 +162,13 @@ def pluck(column_name)
       }
 
       result.map do |attributes|
-        raise ArgumentError, "Pluck expects to select just one attribute: #{attributes.inspect}" unless attributes.one?
-
-        value = klass.initialize_attributes(attributes).values.first
-
-        column.type_cast(value)
+        if attributes.one?
+          value = klass.initialize_attributes(attributes).values.first
+
+          column.type_cast(value)
+        else
+          column_name.collect{|c| attributes[c.to_s]}
+        end
       end
     end
 

activerecord/test/cases/calculations_test.rb

@@ -477,11 +477,26 @@ def test_pluck_with_selection_clause
     assert_equal [50 + 53 + 55 + 60], Account.pluck('SUM(DISTINCT(credit_limit)) as credit_limit')
   end
 
-  def test_pluck_expects_a_single_selection
-    assert_raise(ArgumentError) { Account.pluck 'id, credit_limit' }
+  def test_pluck_expects_a_single_or_multiple_selection
+    assert_nothing_raised(ArgumentError) { Account.pluck 'id, credit_limit' }
   end
 
   def test_plucks_with_ids
     assert_equal Company.all.map(&:id).sort, Company.ids.sort
   end
+
+  def test_pluck_multiple_columns
+    assert_equal [
+      [1, "The First Topic"], [2, "The Second Topic of the day"], 
+      [3, "The Third Topic of the day"], [4, "The Fourth Topic of the day"]
+    ], Topic.order(:id).pluck([:id, :title])
+    assert_equal [
+      [1, "The First Topic", "David"], [2, "The Second Topic of the day", "Mary"], 
+      [3, "The Third Topic of the day", "Carl"], [4, "The Fourth Topic of the day", "Carl"]
+    ], Topic.order(:id).pluck([:id, :title, :author_name])
+    assert_equal [
+      [1, "The First Topic"], [2, "The Second Topic of the day"], 
+      [3, "The Third Topic of the day"], [4, "The Fourth Topic of the day"]
+    ], Topic.order(:id).pluck(:id, :title)
+  end
 end