mybtis实现以下代码：select a.student_name as '学生姓名',c.class_name as '优秀班级', a.student_score as '最高成绩' from student_info a, (select Class_id,max(student_score) as maxs from student_info group by Class_id) b, (select * from student_class where is_class='优') c where c.id=a.Class_id and b.Class_id=c.id and a.student_score=b.maxs;

由于无法确定表结构，以下SQL仅供参考：

SELECT a.student_name AS '学生姓名', c.class_name AS '优秀班级', a.student_score AS '最高成绩'
FROM student_info a
INNER JOIN (
SELECT Class_id, MAX(student_score) AS maxs
FROM student_info
GROUP BY Class_id
) b ON a.Class_id = b.Class_id AND a.student_score = b.maxs
INNER JOIN student_class c ON c.id = a.Class_id AND c.is_class = '优';