class DeleteExcessStudentWorks < ActiveRecord::Migration
  def up
    homework = HomeworkCommon.where(:id => 4818)
    unless homework.empty?
      homework = homework.first
      homework.course.student.each do |student|
        student_works = homework.student_works.where(:user_id => student.student_id).reorder("created_at asc")
        if student_works.count > 1
          if student_works.first.work_status != 0
            student_works.last.destroy
          elsif student_works.last.work_status != 0
            student_works.first.destroy
          else
            student_works.first.destroy
          end
        end
      end
    end
  end

  def down
  end
end