diff --git a/lib/db/upgrade.php b/lib/db/upgrade.php
index ca6e0720654..d00b1982e83 100644
--- a/lib/db/upgrade.php
+++ b/lib/db/upgrade.php
@@ -3527,7 +3527,7 @@ function xmldb_main_upgrade($oldversion) {
                   FROM {event_subscriptions} es
              LEFT JOIN {user} u ON u.id = es.userid
                  WHERE u.deleted = 1 OR u.id IS NULL";
-        $deletedusers = $DB->get_field_sql($sql);
+        $deletedusers = $DB->get_fieldset_sql($sql);
         if ($deletedusers) {
             list($sql, $params) = $DB->get_in_or_equal($deletedusers);