text: /* 查询选修信息系统成绩第2名的学生姓名 */
  select student.name from student, sc, class
      where student.no = sc.sno
          and sc.cno = class.no
          and class.name = '信息系统'
          and sc.grade = (
              select max(sc.grade) from sc, class
                  where sc.cno = class.no
                      and class.name = '信息系统'
                      and sc.grade != (
                          select max(sc.grade) from sc, class
                              where sc.cno = class.no
                                  and class.name = '信息系统'
                      )
          );
  