调整

app/controllers/courses_controller.rb

@@ -1190,9 +1190,9 @@ class CoursesController < ApplicationController
       @all_members = searchmember_by_name(student_homework_score(0, 0, 10,"desc"), q)
     end
 
-    @homeworks = @course.homework_commons.where("publish_time <= '#{Time.now}'").order("IF(ISNULL(publish_time),0,1), publish_time DESC, created_at DESC")
-    @exercises = @course.exercises.where("publish_time <= '#{Time.now}'").order("IF(ISNULL(publish_time),0,1), publish_time DESC, created_at DESC")
-    @tasks = @course.graduation_tasks.where("publish_time <= '#{Time.now}'").order("IF(ISNULL(publish_time),0,1), publish_time DESC, created_at DESC")
+    @homeworks = @course.homework_commons.where("publish_time <= '#{Time.now}'").order("publish_time asc, created_at asc")
+    @exercises = @course.exercises.where("publish_time <= '#{Time.now}'").order("publish_time asc, created_at asc")
+    @tasks = @course.graduation_tasks.where("publish_time <= '#{Time.now}'").order("publish_time asc, created_at asc")
 
     respond_to do |format|
       format.xls {