syllabuses=Syllabus.where("id in #{syllabus_ids} or user_id = #{user.id}").order("updated_at desc")
syllabuses.eachdo|syllabus|
syllabus.courses=syllabus.courses.not_deleted
syllabus.courses=courses.where("syllabus_id = #{syllabus.id}").select("courses.*,(SELECT MAX(updated_at) FROM `course_activities` WHERE course_activities.course_id = courses.id) AS updatetime").order("time desc")