diff --git a/lib/dao/dm.class.php b/lib/dao/dm.class.php
index ff8b494718..2d2056b581 100644
--- a/lib/dao/dm.class.php
+++ b/lib/dao/dm.class.php
@@ -135,7 +135,7 @@ class dm extends dao
         }
 
         /* Format alias. */
-        if($alias and ctype_alnum($alias)) $alias = '"' . $alias . '"';
+        if($alias and !is_numeric($alias) and ctype_alnum($alias)) $alias = '"' . $alias . '"';
 
         return $originField . ' ' .  $alias;
     }