diff --git a/mod/assignment/lib.php b/mod/assignment/lib.php
index e9c062c..004787d 100644
--- a/mod/assignment/lib.php
+++ b/mod/assignment/lib.php
@@ -2887,16 +2887,11 @@ function assignment_print_overview($courses, &$htmlarray) {
 
             // count how many people can submit
             $submissions = 0; // init
-            if ($students = get_users_by_capability($context, 'mod/assignment:submit', '', '', '', '', 0, '', false)) {
-                 foreach ($students as $student) {
-                    if (record_exists_sql("SELECT id FROM {$CFG->prefix}assignment_submissions
-                                           WHERE assignment = $assignment->id AND
-                                               userid = $student->id AND
-                                               teacher = 0 AND
-                                               timemarked = 0")) {
-                        $submissions++;
-                    }
-                }
+            if ($students = get_users_by_capability($context, 'mod/assignment:submit', 'u.id', '', '', '', 0, '', false)) {
+
+                $submissions = get_field_sql("SELECT count(id) FROM {$CFG->prefix}assignment_submissions 
+                                                WHERE assignment = $assignment->id AND teacher = 0 AND timemarked = 0
+                                                AND userid IN (". implode(',', array_keys($students)).")");
             }
 
             if ($submissions) {

: