如果有的人某些科目没考，不一定都考这5科， 有的只考2科：
select a.id, a.n, b.km_s, c.km_y, d.km_y, e.km_h, f.km_w from (select id, n from tt group by n) as a left join (select s as km_s,n from tt where k='数学') as b on a.n=b.n left join (select s as km_y,n from tt where k='语文') as c on a.n=c.n left join (select s as km_y,n from tt where k='英语') as d on a.n=d.n left join (select s as km_h,n from tt where k='化学') as e on a.n=e.n left join (select s as km_w,n from tt where k='物理') as f on a.n=f.n order by a.id;tt: 表名n: 名字k: 科目s: 分数
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在图G中上部分结点孙、李、周三个结点只与下部分结点数学、物理两个结点相连故不满足相异性条件不存在从上部分结点到下部分结点的匹配因此不能安排。