diff --git a/htdocs/core/modules/ticketsup/mod_ticketsup_simple.php b/htdocs/core/modules/ticketsup/mod_ticketsup_simple.php
index 25fabb12377..f0293f78d1f 100644
--- a/htdocs/core/modules/ticketsup/mod_ticketsup_simple.php
+++ b/htdocs/core/modules/ticketsup/mod_ticketsup_simple.php
@@ -73,7 +73,8 @@ class mod_ticketsup_simple extends ModeleNumRefTicketsup
         $posindice = 8;
         $sql = "SELECT MAX(CAST(SUBSTRING(ref FROM " . $posindice . ") AS SIGNED)) as max";
         $sql .= " FROM " . MAIN_DB_PREFIX . "ticketsup";
-        $sql .= " WHERE ref LIKE '" . $this->prefix . "____-%'";
+        $search = $this->prefix . "____-%";
+        $sql .= " WHERE ref LIKE '" . $search ."'";
         $sql .= " AND entity = " . $conf->entity;
         $resql = $db->query($sql);
         if ($resql) {
@@ -107,7 +108,8 @@ class mod_ticketsup_simple extends ModeleNumRefTicketsup
         $posindice = 8;
         $sql = "SELECT MAX(CAST(SUBSTRING(ref FROM " . $posindice . ") AS SIGNED)) as max";
         $sql .= " FROM " . MAIN_DB_PREFIX . "ticketsup";
-        $sql .= " WHERE ref like '" . $this->prefix . "____-%'";
+        $search = $this->prefix . "____-%";
+        $sql .= " WHERE ref LIKE '" . $search ."'";
         $sql .= " AND entity = " . $conf->entity;
 
         $resql = $db->query($sql);