Assignment: Improve speed of assignments stats requests by using iid instead of id - refs BT#15533

main/inc/lib/tracking.lib.php

@@ -3974,7 +3974,7 @@ class Tracking
             $sql = "SELECT count(ip.tool) AS count
                     FROM $tbl_item_property ip
                     INNER JOIN $tbl_document pub
-                    ON (ip.ref = pub.id AND ip.c_id = pub.c_id)
+                    ON (ip.ref = pub.iid AND ip.c_id = pub.c_id)
                     WHERE
                         ip.c_id  = $course_id AND
                         pub.c_id  = $course_id AND
@@ -4038,7 +4038,7 @@ class Tracking
         $sql = "SELECT count(ip.tool) as count
                 FROM $tbl_item_property ip
                 INNER JOIN $tbl_student_publication pub
-                ON (ip.ref = pub.id AND ip.c_id = pub.c_id)
+                ON (ip.ref = pub.iid AND ip.c_id = pub.c_id)
                 WHERE
                     ip.tool='work' AND
                     $conditionToString";