调整

app/helpers/courses_helper.rb

@@ -244,11 +244,7 @@ module CoursesHelper
     course_group_ids = course.group_course_power(user_id)
     course_groups =
         if course_group_ids.present?
-          sql = %Q{
+          course.course_groups.where(id: course_group_ids).includes(:course_members)
-                    SELECT * FROM course_groups WHERE id in(SELECT course_group_id FROM teacher_course_groups WHERE id
-                      IN(#{course_group_ids.join(",")})) order by position ASC
-                  }
-          CourseGroup.find_by_sql(sql)
         else
           course.course_groups.includes(:course_members)
         end