初学Oracle，请教个各位老师们个题目，感激不尽

[hybaididi]

有两张表：

表 1
STUDNAME COURSENAME CSCORE USCORE
--------------------------------
jack A 80 1
jack B 60 5
jack C 70 3
rose A 95 1
rose B 85 5
rose C 75 3
lucy A 45 1
lucy B 55 5
lucy C 50 3
lily A 25 1
lily B 15 5
lily C 10 3

表2
姓名 A B C 总学分
--------------------------------
jack 80 60 70 9
rose 95 85 75 9
lucy 45 55 50 9
lily 25 15 10 9

1. 从表1获取数据，格式化输出为表2。
2. 从表2读取数据，格式化输出为表1。
PS： 脚本关键语句最好有注释

[大明湖畔_帅锅]

create table t1 (STUDNAME varchar2(20), COURSENAME varchar2(10), CSCORE number(3), USCORE number(5));

insert into t1 values ('jack','A',80,1);
insert into t1 values ('jack','B',60,5);
insert into t1 values ('jack','C',70,3);
insert into t1 values ('rose','A',95,1);
insert into t1 values ('rose','B',85,5);
insert into t1 values ('rose','C',75,3);
insert into t1 values ('lucy','A',45,1);
insert into t1 values ('lucy','B',55,5);
insert into t1 values ('lucy','C',50,3);
insert into t1 values ('lily','A',25,1);
insert into t1 values ('lily','B',15,5);
insert into t1 values ('lily','C',10,3);


select STUDNAME,
       sum(decode(COURSENAME,'A',CSCORE,0)) A, --判断每行的科目和成绩 根据姓名合并多行各科成绩
       sum(decode(COURSENAME,'B',CSCORE,0)) B,
       sum(decode(COURSENAME,'C',CSCORE,0)) C,
       sum(USCORE) USCORE
from t1
group by STUDNAME


   STUDNAME    A    B    C    USCORE
-------------------------------------------------
1    rose    95    85    75    9
2    jack    80    60    70    9
3    lucy    45    55    50    9
4    lily    25    15    10    9