2 files changed, 12 insertions, 5 deletions
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
index 566550cbe2..aabedf15e9 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
@@ -65,8 +65,7 @@ module ActiveRecord
       # Appends a primary key definition to the table definition.
       # Can be called multiple times, but this is probably not a good idea.
       def primary_key(name, type = :primary_key, options = {})
-        options[:primary_key] = true
-        column(name, type, options)
+        column(name, type, options.merge(:primary_key => true))
       end
 
       # Returns a ColumnDefinition for the column with name +name+.
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
index 9c0c4e3ef0..6e1f43cce6 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
@@ -706,12 +706,20 @@ module ActiveRecord
       end
 
       # SELECT DISTINCT clause for a given set of columns and a given ORDER BY clause.
-      # Both PostgreSQL and Oracle overrides this for custom DISTINCT syntax.
       #
-      #   distinct("posts.id", "posts.created_at desc")
+      #   distinct("posts.id", ["posts.created_at desc"])
       #
       def distinct(columns, order_by)
-        "DISTINCT #{columns}"
+        "DISTINCT #{columns_for_distinct(columns, order_by)}"
+      end
+
+      # Given a set of columns and an ORDER BY clause, returns the columns for a SELECT DISTINCT.
+      # Both PostgreSQL and Oracle overrides this for custom DISTINCT syntax - they
+      # require the order columns appear in the SELECT.
+      #
+      #   columns_for_distinct("posts.id", ["posts.created_at desc"])
+      def columns_for_distinct(columns, orders)
+        columns
       end
 
       # Adds timestamps (+created_at+ and +updated_at+) columns to the named table.