diff --git a/classes/anonymous.php b/classes/anonymous.php
index c098dc8bce..ea593c94d6 100644
--- a/classes/anonymous.php
+++ b/classes/anonymous.php
@@ -94,7 +94,7 @@ public static function get_userid_mapping($moodleoverflow, $discussionid) {
         $userids = $DB->get_records_sql(
             'SELECT userid ' .
             'FROM {moodleoverflow_posts} ' .
-            'WHERE discussion = :discussion' .
+            'WHERE discussion = :discussion ' .
             'GROUP BY userid ' .
             'ORDER BY MIN(created) ASC;', ['discussion' => $discussionid]);