select track_id from lorsm_student_track where user_id = :user_id select community_id from lorsm_student_bookmark where user_id = :user_id update lorsm_student_track set user_id = :to_user_id where user_id = :from_user_id update lorsm_student_bookmark set user_id = :to_user_id where user_id = :from_user_id select count(1) as result from ( select distinct l.course_id from lorsm_student_track l where l.community_id=:comm_id group by l.course_id) as t