diff --git a/quiz.module b/quiz.module
index 4612590..9613224 100644
--- a/quiz.module
+++ b/quiz.module
@@ -2597,17 +2597,22 @@ function quiz_update_max_score_properties($quizzes_to_update) {
 
   db_update('quiz_node_results')
     ->expression('score',
-      'ROUND(
-        100 * (
-          SELECT COALESCE (SUM(a.points_awarded), 0)
-          FROM {quiz_node_results_answers} a
-          WHERE a.result_id = {quiz_node_results}.result_id
-        ) / (
-          SELECT max_score
-          FROM {quiz_node_properties} qnp
-          WHERE qnp.vid = {quiz_node_results}.vid
-        )
-      )')
+      'case 
+      	when (SELECT max_score FROM {quiz_node_properties} qnp WHERE qnp.vid = {quiz_node_results}.vid)=0 
+      	  then 0
+        else
+          ROUND(
+            100 * (
+              SELECT COALESCE (SUM(a.points_awarded), 0)
+              FROM {quiz_node_results_answers} a
+              WHERE a.result_id = {quiz_node_results}.result_id
+            ) / (
+              SELECT max_score
+              FROM {quiz_node_properties} qnp
+              WHERE qnp.vid = {quiz_node_results}.vid
+            )        
+      	  ) 
+      end')
     ->condition('vid', $quizzes_to_update, 'IN')
     ->execute();
 }