call to present? is not necessary

activerecord/lib/active_record/relation/calculations.rb

@@ -166,8 +166,7 @@ module ActiveRecord
       if operation == "count"
         column_name ||= (select_for_count || :all)
 
-        joins = arel.joins(arel)
-        if joins.present? && joins =~ /LEFT OUTER/i
+        if arel.joins(arel) =~ /LEFT OUTER/i
           distinct = true
           column_name = @klass.primary_key if column_name == :all
         end