commit 8362a726d51c1df48955ff45d14581b804135248
Author: trevor-c <trevor.cunningham@uregina.ca>
Date:   Fri Jun 20 15:08:58 2014 -0600

    fix rank calculation - no longer include grade items from users no longer enrolled in the course

diff --git a/grade/report/overview/lib.php b/grade/report/overview/lib.php
index 8c279f7..4812f41 100644
--- a/grade/report/overview/lib.php
+++ b/grade/report/overview/lib.php
@@ -181,7 +181,10 @@ class grade_report_overview extends grade_report {
                 } else if ($this->showrank[$course->id] && !is_null($finalgrade)) {
                     /// find the number of users with a higher grade
                     /// please note this can not work if hidden grades involved :-( to be fixed in 2.0
-                    $params = array($finalgrade, $course_item->id);
+                    
+                    /* Correct issue with rank gathering grades from users who are no longer enrolled
+                    //WRONG - includes grade history or unenrolled users*/
+                    /*$params = array($finalgrade, $course_item->id);
                     $sql = "SELECT COUNT(DISTINCT(userid))
                               FROM {grade_grades}
                              WHERE finalgrade IS NOT NULL AND finalgrade > ?
@@ -189,7 +192,35 @@ class grade_report_overview extends grade_report {
                     $rank = $DB->count_records_sql($sql, $params) + 1;
 
                     $data[] = "$rank/$numusers";
-
+                    */
+                    
+                    $context = get_context_instance(CONTEXT_COURSE, $course->id);
+                    
+                    // This is the correct way find the number of users with a higher grade thet ARE STILL ENROLLED in the course.
+                    $sql = "SELECT COUNT(DISTINCT(g.userid))
+                              FROM {grade_grades} g
+                                INNER JOIN {role_assignments} r
+                              ON r.userid = g.userid
+                         WHERE finalgrade IS NOT NULL AND finalgrade > ?
+                            AND g.itemid = ?
+                            AND(r.contextid = ?)
+                            AND r.roleid IN (?)";
+                            
+                    $rank = $DB->count_records_sql($sql, array($finalgrade, $course_item->id, $context->id,$CFG->gradebookroles)) + 1;
+                    
+                    // Counts the sql for gradeable users in the course
+                    $sql = "SELECT count(u.id)
+                              FROM {role_assignments} r
+                                  JOIN {user} u
+                                  ON u.id = r.userid
+                                  WHERE (r.contextid = ?)
+                                  AND r.roleid IN (?)
+                                  AND u.deleted = 0";
+                    
+                    $numusers = $DB->count_records_sql($sql, array($context->id,$CFG->gradebookroles));
+                    
+                    $data[] = "$rank/$numusers"; // total course users (still enrolled)
+                    
                 } else {
                     // No grade, no rank.
                     // Or this course wants rank hidden.