diff --git a/dblayeroo.php b/dblayeroo.php
index 2317662..4b670ec 100644
--- a/dblayeroo.php
+++ b/dblayeroo.php
@@ -1577,9 +1577,6 @@ class dblayeroo
           // expression, if not already done
           if ($this->groupByExpression === null)
           {
-            if ($this->displayColumn === null)
-              $this->groupByExpression = array_keys ($this->fields);
-            else
               $this->groupByExpression = $this->displayColumn;
           }
           if ($func === "GROUP_CONCAT" && ($pos = strpos ($name, ",'")))