一个查询问题，主要是要增加说明列 求指教

Question

事件描述：公司人力资源系统的数据库记录了每位员工的培训信息，有如下3张表：
STAFF (Sno,Sname,Sdept,Sage)   Sno,Sname,Sdept,Sage 分别代表学号、学员姓名、所属单位、学员年龄
COURSE (Cno,Cname )        Cno,Cname       分别代表课程编号、课程名称
SCRELATION ( Sno,Cno,Grade )    Sno,Cno,Grade     分别代表学号、所选修的课程编号、学习成绩查询每个单位所选修课程的最高分和最低分的学员学号、姓名、所属单位、学习成绩，并增加最高（低）分说明列。
这个如何解决呢？主要是如何增加说明列！！求各位大哥指教！！！麻烦给出详细脚本谢谢..！！

Answer 1

select *
  from (select mingrade.sdept,
               mingrade.cname,
               mingrade.ming 最低分,
               grade.sno,
               grade.sname
          from (select STAFF.Sdept,
                       COURSE.CNAME,
                       min(to_number(SCRELATION.Grade)) as ming
                  from STAFF, COURSE, SCRELATION
                 where STAFF.Sno = SCRELATION.Sno
                   and SCRELATION.Cno = COURSE.Cno
                 group by STAFF.Sdept, COURSE.CNAME
                 order by STAFF.Sdept) mingrade,
               
               (select STAFF.Sno,
                       STAFF.Sname,
                       COURSE.Cname,
                       SCRELATION.Grade,
                       STAFF.Sdept
                  from STAFF, COURSE, SCRELATION
                 where STAFF.Sno = SCRELATION.Sno
                   and SCRELATION.Cno = COURSE.Cno) grade
         where mingrade.cname = grade.cname
           and mingrade.Sdept = grade.sdept
           and mingrade.ming = grade.grade
         order by mingrade.sdept) zxcj,
       
       (select maxgrade.sdept,
               maxgrade.cname,
               maxgrade.maxg  最高分,
               grade.sno,
               grade.sname
          from (select STAFF.Sdept,
                       COURSE.CNAME,
                       max(to_number(SCRELATION.Grade)) as maxg
                  from STAFF, COURSE, SCRELATION
                 where STAFF.Sno = SCRELATION.Sno
                   and SCRELATION.Cno = COURSE.Cno
                 group by STAFF.Sdept, COURSE.CNAME
                 order by STAFF.Sdept) maxgrade,
               (select STAFF.Sno,
                       STAFF.Sname,
                       COURSE.Cname,
                       SCRELATION.Grade,
                       STAFF.Sdept
                  from STAFF, COURSE, SCRELATION
                 where STAFF.Sno = SCRELATION.Sno
                   and SCRELATION.Cno = COURSE.Cno) grade
         where maxgrade.cname = grade.cname
           and maxgrade.Sdept = grade.sdept
           and maxgrade.maxg = grade.grade
         order by maxgrade.sdept) zdcj
 where zxcj.sdept = zdcj.sdept
   and zxcj.cname = zdcj.cname

Answer 2

SELECT SNO,
       SNAME,
       SDEPT,
       GRADE,
       DECODE(GRADE, MAX_, '最高分', MIN_, '最低分', '程序错误')
  FROM SELECT T1.SNO,
              T1.SNAME,
              T1.SDEPT,
              T3.GRADE,
              MAX(T3.GRADE) OVER(PARTITION BY T1.SDEPT) MAX_,
              MIN(T3.GRADE) OVER(PARTITION BY T1.SDEPT) MIN_
         FROM STAFF T1, COURSE T2, SCRELATION T3
        WHERE T3.SNO = T1.SNO
          AND T3.CNO = T2.CNO)
        WHERE (GRADE = MAX_ OR GREAD = MIN_)

Answer 3

select *
  from (select mingrade.sdept,
               mingrade.cname,
               mingrade.ming 最低分,
               grade.sno,
               grade.sname
          from (select STAFF.Sdept,
                       COURSE.CNAME,
                       min(to_number(SCRELATION.Grade)) as ming
                  from STAFF, COURSE, SCRELATION
                 where STAFF.Sno = SCRELATION.Sno
                   and SCRELATION.Cno = COURSE.Cno
                 group by STAFF.Sdept, COURSE.CNAME
                 order by STAFF.Sdept) mingrade,
               
               (select STAFF.Sno,
                       STAFF.Sname,
                       COURSE.Cname,
                       SCRELATION.Grade,
                       STAFF.Sdept
                  from STAFF, COURSE, SCRELATION
                 where STAFF.Sno = SCRELATION.Sno
                   and SCRELATION.Cno = COURSE.Cno) grade
         where mingrade.cname = grade.cname
           and mingrade.Sdept = grade.sdept
           and mingrade.ming = grade.grade
         order by mingrade.sdept) zxcj,
       
       (select maxgrade.sdept,
               maxgrade.cname,
               maxgrade.maxg 最高分,
               grade.sno,
               grade.sname
          from (select STAFF.Sdept,
                       COURSE.CNAME,
                       max(to_number(SCRELATION.Grade)) as maxg
                  from STAFF, COURSE, SCRELATION
                 where STAFF.Sno = SCRELATION.Sno
                   and SCRELATION.Cno = COURSE.Cno
                 group by STAFF.Sdept, COURSE.CNAME
                 order by STAFF.Sdept) maxgrade,
               (select STAFF.Sno,
                       STAFF.Sname,
                       COURSE.Cname,
                       SCRELATION.Grade,
                       STAFF.Sdept
                  from STAFF, COURSE, SCRELATION
                 where STAFF.Sno = SCRELATION.Sno
                   and SCRELATION.Cno = COURSE.Cno) grade
         where maxgrade.cname = grade.cname
           and maxgrade.Sdept = grade.sdept
           and maxgrade.maxg = grade.grade
         order by maxgrade.sdept) zdcj
 where zxcj.sdept = zdcj.sdept
   and zxcj.cname = zdcj.cname