Index: modules/user/user.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/user/user.module,v
retrieving revision 1.745.2.26
diff -u -p -r1.745.2.26 user.module
--- modules/user/user.module	7 Jan 2008 02:30:35 -0000	1.745.2.26
+++ modules/user/user.module	7 Feb 2008 16:28:40 -0000
@@ -599,7 +599,7 @@ function user_block($op = 'list', $delta
           // Perform database queries to gather online user lists.  We use s.timestamp
           // rather than u.access because it is much faster.
           $anonymous_count = sess_count($interval);
-          $authenticated_users = db_query('SELECT DISTINCT u.uid, u.name, s.timestamp FROM {users} u INNER JOIN {sessions} s ON u.uid = s.uid WHERE s.timestamp >= %d AND s.uid > 0 ORDER BY s.timestamp DESC', $interval);
+          $authenticated_users = db_query('SELECT u.uid, u.name, max(s.timestamp) AS max_timestamp FROM {users} u INNER JOIN {sessions} s ON u.uid = s.uid WHERE s.timestamp >= %d AND s.uid > 0 GROUP BY u.uid, u.name ORDER BY max_timestamp DESC', $interval);   
           $authenticated_count = db_num_rows($authenticated_users);
 
           // Format the output with proper grammar.