diff --git a/lib/active_record/connection_adapters/oracle_enhanced_adapter.rb b/lib/active_record/connection_adapters/oracle_enhanced_adapter.rb
index 2c561fd24..d625d334a 100644
--- a/lib/active_record/connection_adapters/oracle_enhanced_adapter.rb
+++ b/lib/active_record/connection_adapters/oracle_enhanced_adapter.rb
@@ -662,7 +662,7 @@ def columns_for_distinct(columns, orders) # :nodoc:
           }.reject(&:blank?).map.with_index { |column, i|
             "FIRST_VALUE(#{column}) OVER (PARTITION BY #{columns} ORDER BY #{column}) AS alias_#{i}__"
           }
-        [super, *order_columns].join(", ")
+        (order_columns << super).join(", ")
       end
 
       def temporary_table?(table_name) # :nodoc: