我的评分显示错误

app/controllers/student_work_controller.rb

@@ -21,7 +21,7 @@ class StudentWorkController < ApplicationController
           @stundet_works = search_homework_member @homework.student_works.select("*,IF(final_score is null,null,final_score - absence_penalty - late_penalty) as score").order("#{@order} #{@b_sort}"),@name
         end
       else #剩余情况： 学生 && 非匿评作业 如果未提交作品，只能看到自己的，提交了作品，能看到所有作品
-        my_work = @homework.student_works.select("*,final_score - absence_penalty - late_penalty as score").where(:user_id => User.current.id)
+        my_work = @homework.student_works.select("*,IF(final_score is null,null,final_score - absence_penalty - late_penalty) as score").where(:user_id => User.current.id)
         if my_work.empty?
           @stundet_works = []
         else