diff --git a/lib/questionlib.php b/lib/questionlib.php
index 6abc4cdf853..f861f921648 100644
--- a/lib/questionlib.php
+++ b/lib/questionlib.php
@@ -645,7 +645,7 @@ function question_delete_course($course, $feedback=true) {
     //Cache some strings
     $strcatdeleted = get_string('unusedcategorydeleted', 'quiz');
     $coursecontext = get_context_instance(CONTEXT_COURSE, $course->id);
-    $categoriescourse = $DB->get_records('question_categories', array('contextid'=>$coursecontext->id), 'parent', 'id, parent, name');
+    $categoriescourse = $DB->get_records('question_categories', array('contextid'=>$coursecontext->id), 'parent', 'id, parent, name, contextid');
 
     if ($categoriescourse) {
 
@@ -809,7 +809,7 @@ function question_delete_activity($cm, $feedback=true) {
     //Cache some strings
     $strcatdeleted = get_string('unusedcategorydeleted', 'quiz');
     $modcontext = get_context_instance(CONTEXT_MODULE, $cm->id);
-    if ($categoriesmods = $DB->get_records('question_categories', array('contextid'=>$modcontext->id), 'parent', 'id, parent, name')){
+    if ($categoriesmods = $DB->get_records('question_categories', array('contextid'=>$modcontext->id), 'parent', 'id, parent, name, contextid')){
         //Sort categories following their tree (parent-child) relationships
         //this will make the feedback more readable
         $categoriesmods = sort_categories_by_tree($categoriesmods);
@@ -2265,8 +2265,9 @@ function sort_categories_by_tree(&$categories, $id = 0, $level = 1) {
     //If level = 1, we have finished, try to look for non processed categories (bad parent) and sort them too
     if ($level == 1) {
         foreach ($keys as $key) {
-            //If not processed and it's a good candidate to start (because its parent doesn't exist in the course)
-            if (!isset($categories[$key]->processed) && !$DB->record_exists('question_categories', array('course'=>$categories[$key]->course, 'id'=>$categories[$key]->parent))) {
+            // If not processed and it's a good candidate to start (because its parent doesn't exist in the course)
+            if (!isset($categories[$key]->processed) && !$DB->record_exists(
+                    'question_categories', array('contextid'=>$categories[$key]->contextid, 'id'=>$categories[$key]->parent))) {
                 $children[$key] = $categories[$key];
                 $categories[$key]->processed = true;
                 $children = $children + sort_categories_by_tree($categories, $children[$key]->id, $level+1);