Initial commit to support distinct_columns

lib/active_record/connection_adapters/oracle_enhanced_adapter.rb

@@ -1234,7 +1234,7 @@ def has_primary_key?(table_name, owner=nil, desc_table_name=nil, db_link=nil) #:
       # making every row the same.
       #
       #   distinct("posts.id", "posts.created_at desc")
-      def distinct(columns, order_by) #:nodoc:
+      def distinct_columns(columns, order_by) #:nodoc:
         # construct a valid DISTINCT clause, ie. one that includes the ORDER BY columns, using
         # FIRST_VALUE such that the inclusion of these columns doesn't invalidate the DISTINCT
         order_columns = order_by.map { |c|
@@ -1244,7 +1244,14 @@ def distinct(columns, order_by) #:nodoc:
           }.reject(&:blank?).map.with_index { |c,i| 
             "FIRST_VALUE(#{c}) OVER (PARTITION BY #{columns} ORDER BY #{c}) AS alias_#{i}__" 
           }
-          [super].concat(order_columns).join(', ')
+          # Return as `String`
+          puts super.concat(order_columns).join(', ').class
+          puts super.concat(order_columns).join(', ')
+          super.concat(order_columns).join(', ')
+          # Return as `Array`
+          #puts super.concat(order_columns).class
+          #puts super.concat(order_columns)
+          #super.concat(order_columns)
       end
 
       def temporary_table?(table_name) #:nodoc: