diff --git a/htdocs/mrp/ajax/interface.php b/htdocs/mrp/ajax/interface.php
index 639e0d21642..1c0ebb4f73d 100644
--- a/htdocs/mrp/ajax/interface.php
+++ b/htdocs/mrp/ajax/interface.php
@@ -62,7 +62,7 @@ if($action == 'updateselectbatchbywarehouse' && $permissiontoproduce) {
 	$sql .= " FROM " . MAIN_DB_PREFIX . "product_batch as pb";
 	$sql .= " JOIN " . MAIN_DB_PREFIX . "product_stock as ps on ps.rowid = pb.fk_product_stock";
 	$sql .= " JOIN " . MAIN_DB_PREFIX . "entrepot as e on e.rowid = ps.fk_entrepot AND e.entity IN (" . getEntity('stock') . ")";
-	$sql .= " WHERE ps.fk_product = '" . $fk_product . "'";
+	$sql .= " WHERE ps.fk_product = " .((int) $fk_product);
 	if ($batch_id > 0) $sql.= " AND pb.batch = '" . $batch_id . "'";
 	$sql .= " ORDER BY e.ref, pb.batch";