MDL-25623 fix incorrect use of DISTINCT on text fields

enrol/meta/locallib.php

@@ -148,22 +148,21 @@ public function user_unenrolled($ue) {
         //note: do not test if plugin enabled, we want to keep removing previously linked courses
 
         // look for unenrolment candidates - it may be possible that user has multiple enrolments...
-        $sql = "SELECT DISTINCT e.*
+        $sql = "SELECT e.*
                   FROM {enrol} e
                   JOIN {user_enrolments} ue ON (ue.enrolid = e.id AND ue.userid = :userid)
                   JOIN {enrol} pe ON (pe.courseid = e.customint1 AND pe.enrol <> 'meta' AND pe.courseid = :courseid)
              LEFT JOIN {user_enrolments} pue ON (pue.enrolid = pe.id AND pue.userid = ue.userid)
                  WHERE pue.id IS NULL";
         $params = array('courseid'=>$ue->courseid, 'userid'=>$ue->userid);
 
-        if (!$enrols = $DB->get_records_sql($sql, $params)) {
-            return true;
-        }
+        $rs = $DB->get_recordset_sql($sql, $params);
 
         $plugin = enrol_get_plugin('meta');
-        foreach ($enrols as $enrol) {
+        foreach ($rs as $enrol) {
             $plugin->unenrol_user($enrol, $ue->userid);
         }
+        $rs->close();
 
         return true;
     }