diff --git a/includes/common.php b/includes/common.php
index 12ba52771..1fc1e648c 100644
--- a/includes/common.php
+++ b/includes/common.php
@@ -436,6 +436,7 @@ function get_dev_entity_state($device) {
 }
 
 function get_dev_attrib($device, $attrib_type, $attrib_value='') {
+    $sql = '';
     $params = array($device['device_id'], $attrib_type);
     if (!empty($attrib_value)) {
         $sql = " AND `attrib_value`=?";