diff --git a/htdocs/core/class/html.form.class.php b/htdocs/core/class/html.form.class.php
index cac859c53b5..223f34a7dce 100644
--- a/htdocs/core/class/html.form.class.php
+++ b/htdocs/core/class/html.form.class.php
@@ -2095,7 +2095,7 @@ class Form
 		}
 		else
 		{
-		    $selectFieldsGrouped = ", p.stock";
+		    $selectFieldsGrouped = ", ".$db->ifsql("p.stock IS NULL", 0, "p.stock")." AS stock";
 		}
 
 		$sql = "SELECT ";