diff --git a/application/Preordernotification/PreordernotificationModel.php b/application/Preordernotification/PreordernotificationModel.php
index acc2e5af0..bc5f94581 100644
--- a/application/Preordernotification/PreordernotificationModel.php
+++ b/application/Preordernotification/PreordernotificationModel.php
@@ -162,14 +162,14 @@ class PreordernotificationModel {
     if(array_key_exists("send_finish", $filter)) {
       $send_finish = $filter['send_finish'];
       if($send_finish === null) {
-        $where .= " AND Preordernotification.send_finish = NULL";
+        $where .= " AND Preordernotification.send_finish IS NULL";
       }
     }
     
     if(array_key_exists("send_lock", $filter)) {
       $send_lock = $filter['send_lock'];
       if($send_lock === null) {
-        $where .= " AND Preordernotification.send_lock = NULL";
+        $where .= " AND Preordernotification.send_lock IS NULL";
       }
     }
     
diff --git a/application/PreordernotificationLog/PreordernotificationLogModel.php b/application/PreordernotificationLog/PreordernotificationLogModel.php
index bd82fbb81..3b088d453 100644
--- a/application/PreordernotificationLog/PreordernotificationLogModel.php
+++ b/application/PreordernotificationLog/PreordernotificationLogModel.php
@@ -4,6 +4,7 @@ class PreordernotificationLogModel {
   public $preordernotification_id;
   public $preorder_id;
   public $email;
+  public $sent;
   public $create_by = null;
   public $edit_by = null;
   public $create = null;