首先创建示例表，再初始化几条测试数据

create table t_score

(

id number primary key,

student_id  number(3),

student_name char(8) not null,

sub_name varchar2(20),

score number(10,2)

);

insert into t_score (id, student_id, student_name, sub_name, score)

values (1, 1, 'John', 'c#', 90);

insert into t_score (id, student_id, student_name, sub_name, score)

values (2, 1, 'John', 'php', 97);

insert into t_score (id, student_id, student_name, sub_name, score)

values (3, 1, 'John', 'java', 85);

insert into t_score (id, student_id, student_name, sub_name, score)

values (4, 2, 'Lili', 'c#', 75);

insert into t_score (id, student_id, student_name, sub_name, score)

values (5, 2, 'Lili', 'php', 55);

insert into t_score (id, student_id, student_name, sub_name, score)

values (6, 2, 'Lili', 'java', 91);

insert into t_score (id, student_id, student_name, sub_name, score)

values (7, 3, 'Tom', 'c#', 40);

insert into t_score (id, student_id, student_name, sub_name, score)

values (8, 3, 'Tom', 'php', 89);

insert into t_score (id, student_id, student_name, sub_name, score)

values (9, 3, 'Tom', 'java', 98);

commit;