9.查询和" 01 "号的同学学习的课程完全相同的其他同学的信息的一种实现方式，及group_concat实现group by组内排序

select
    *
from
    student
where
    s_id in (
    select
        s_id
    from
        score t1
    group by
        s_id
    having
        group_concat(c_id) = (
            select group_concat(c_id) as str2
        from
            score
        where
            s_id = ‘01‘)
        and s_id != ‘01‘);

select
    *
from
    student
where
    sid in (
    select
        sid
    from
        sc t1
    group by
        sid
    having
        group_concat(cid ORDER BY cid) = (
            select group_concat(cid ORDER BY cid) as str2
        from
            sc
        where
            sid = ‘01‘)
        and sid != ‘01‘);