diff --git a/app/models/cost_query/sql_statement.rb b/app/models/cost_query/sql_statement.rb
index fc1a5d493e..b323513f77 100644
--- a/app/models/cost_query/sql_statement.rb
+++ b/app/models/cost_query/sql_statement.rb
@@ -275,6 +275,7 @@ class CostQuery::SqlStatement
           @group_by << field_name_for(e)
         end
       end
+      @group_by.uniq!
     end
   end