cc

app/helpers/exercises_helper.rb

@@ -214,7 +214,7 @@ module ExercisesHelper
 
         # percent = commit_user_ids > 0 ? (all_user_count / commit_user_ids.to_f).round(3)*100 : 0.0
         user_right_count = effictive_users.where("score > 0.0").pluck(:user_id).uniq
-        unanswer_user_count = effictive_users.where("score < 0.0 and answer_text != ''").pluck(:user_id).uniq
+        unanswer_user_count = effictive_users.where("score < 0.0 and answer_text is null or answer_text = ''").pluck(:user_id).uniq
         user_wrong_counts = effictive_users.where("score < 0.0 and answer_text is not null and answer_text != ''").pluck(:user_id).uniq
         user_wrong_count = (user_wrong_counts - user_right_count - unanswer_user_count).size