Index: course/report/participation/index.php
===================================================================
--- course/report/participation/index.php	(revision 517)
+++ course/report/participation/index.php	(working copy)
@@ -170,26 +170,25 @@
 
         switch ($action) {
             case 'view':
-                $actionsql = 'l.action IN (\''.implode('\',\'', $viewnames).'\' )';
+                $actionsql = 'action IN (\''.implode('\',\'', $viewnames).'\' )';
                 break;
             case 'post':
-                $actionsql = 'l.action IN (\''.implode('\',\'', $postnames).'\' )';
+                $actionsql = 'action IN (\''.implode('\',\'', $postnames).'\' )';
                 break;
             default:
                 // some modules have stuff we want to hide, ie mail blocked etc so do actually need to limit here.
-                $actionsql = 'l.action IN (\''.implode('\',\'', array_merge($viewnames, $postnames)).'\' )';
+                $actionsql = 'action IN (\''.implode('\',\'', array_merge($viewnames, $postnames)).'\' )';
         }
 
         $relatedcontexts = get_related_contexts_string($context);
 
         $sql = "SELECT ra.userid, u.firstname, u.lastname, u.idnumber, COUNT(l.action) AS count
-                  FROM {$CFG->prefix}role_assignments ra
+                  FROM (SELECT * FROM {$CFG->prefix}role_assignments WHERE contextid $relatedcontexts AND roleid = $roleid) ra
                        JOIN {$CFG->prefix}user u           ON u.id = ra.userid
-                       LEFT OUTER JOIN {$CFG->prefix}log l ON (l.userid = ra.userid AND l.cmid = $instanceid AND l.time > $timefrom AND $actionsql)
-                 WHERE ra.contextid $relatedcontexts AND ra.roleid = $roleid";
+                       LEFT OUTER JOIN (SELECT * FROM {$CFG->prefix}log WHERE cmid = $instanceid AND time > $timefrom AND $actionsql) l ON l.userid = ra.userid";
 
         if ($table->get_sql_where()) {
-            $sql .= ' AND '.$table->get_sql_where(); //initial bar
+            $sql .= ' WHERE '.$table->get_sql_where(); //initial bar
         }
 
         $sql .= " GROUP BY ra.userid, u.firstname, u.lastname, u.idnumber";
@@ -199,15 +198,13 @@
         }
 
         $countsql = "SELECT COUNT(DISTINCT(ra.userid))
-                       FROM {$CFG->prefix}role_assignments ra
-                            JOIN {$CFG->prefix}user u           ON u.id = ra.userid
-                            LEFT OUTER JOIN {$CFG->prefix}log l ON (l.userid = ra.userid AND l.cmid = $instanceid AND l.time > $timefrom AND $actionsql)
-                      WHERE ra.contextid $relatedcontexts AND ra.roleid = $roleid";
+                       FROM (SELECT * FROM {$CFG->prefix}role_assignments WHERE contextid $relatedcontexts AND roleid = $roleid) ra
+                            JOIN {$CFG->prefix}user u           ON u.id = ra.userid";
 
         $totalcount = count_records_sql($countsql);
 
         if ($table->get_sql_where()) {
-            $matchcount = count_records_sql($countsql.' AND '.$table->get_sql_where());
+            $matchcount = count_records_sql($countsql.' WHERE '.$table->get_sql_where());
         } else {
             $matchcount = $totalcount;
         }