MDL-27703 gradebook: altered an sql query in the user report. join wi…

…th no on clause causes an error in some DBs

grade/report/user/lib.php

@@ -651,7 +651,7 @@ function calculate_averages() {
             // Then left join with grade_grades and look for rows with null final grade (which includes grade items with no grade_grade)
             $sql = "SELECT gi.id, COUNT(u.id) AS count
                       FROM {grade_items} gi
-                      JOIN {user} u
+                      JOIN {user} u ON u.deleted = 0
                       JOIN ($enrolledsql) je ON je.id = u.id
                       JOIN (
                                SELECT DISTINCT ra.userid
@@ -660,10 +660,9 @@ function calculate_averages() {
                                   AND ra.contextid " . get_related_contexts_string($this->context) . "
                            ) rainner ON rainner.userid = u.id
                       LEFT JOIN {grade_grades} gg
-                           ON (gg.itemid = gi.id AND gg.userid = u.id AND gg.finalgrade IS NOT NULL AND gg.hidden = 0)
+                             ON (gg.itemid = gi.id AND gg.userid = u.id AND gg.finalgrade IS NOT NULL AND gg.hidden = 0)
                       $groupsql
                      WHERE gi.courseid = :courseid
-                           AND u.deleted = 0
                            AND gg.finalgrade IS NULL
                            $groupwheresql
                   GROUP BY gi.id";