diff --git a/message/lib.php b/message/lib.php
index 0f8cf4ca29a..fe65e9d45ac 100644
--- a/message/lib.php
+++ b/message/lib.php
@@ -1023,17 +1023,12 @@ function message_get_participants() {
 
     global $CFG;
 
-    return get_records_sql("SELECT DISTINCT u.id, u.id
-                              FROM {$CFG->prefix}user as u,
-                                   {$CFG->prefix}message as m, 
-                                   {$CFG->prefix}message_read as mr,
-                                   {$CFG->prefix}message_contacts as mc
-                             WHERE m.useridfrom = u.id 
-                                OR m.useridto = u.id
-                                OR mr.useridfrom = u.id
-                                OR mr.useridto = u.id
-                                OR mc.userid = u.id
-                                OR mc.contactid = u.id");
+    return get_records_sql("SELECT useridfrom,useridfrom FROM {$CFG->prefix}message
+                           UNION SELECT useridto,useridto FROM {$CFG->prefix}message
+                           UNION SELECT useridfrom,useridfrom FROM {$CFG->prefix}message_read
+                           UNION SELECT useridto,useridto FROM {$CFG->prefix}message_read
+                           UNION SELECT userid,userid FROM {$CFG->prefix}message_contacts
+                           UNION SELECT contactid,contactid from {$CFG->prefix}message_contacts");
 }
 
 ?>