diff --git a/db/migrations/5.5.25_alter_calendar_tables.php b/db/migrations/5.5.25_alter_calendar_tables.php
index b1f477b0c1c8374b83b430f55ad2566102ca7326..e9bf455287a633d1e94c4b16ad42b530aaa5ec69 100644
--- a/db/migrations/5.5.25_alter_calendar_tables.php
+++ b/db/migrations/5.5.25_alter_calendar_tables.php
@@ -130,7 +130,7 @@ class AlterCalendarTables extends Migration
                     IF(`permission` = '4', 'WRITE', IF(`permission` = '2', 'READ', '')) AS calendar_permissions,
                    `mkdate`, `chdate`
                    FROM `calendar_user`
-            ON DUPLICATE KEY UPDATE `calendar_permissions` = calendar_permissions"
+            ON DUPLICATE KEY UPDATE `calendar_permissions` = VALUES(calendar_permissions)"
         );
 
         $db->exec("DROP TABLE `calendar_user`");