1 files changed, 4 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb b/activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb
index 18fdfa29ec..c01a64e354 100644
--- a/activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb
@@ -577,6 +577,10 @@ module ActiveRecord
         where_sql
       end
 
+      def join_to_update(update, select) #:nodoc:
+        update.table select.ast.cores.last.source
+      end
+
       protected
         def quoted_columns_for_index(column_names, options = {})
           length = options[:length] if options.is_a?(Hash)