为管理岗位业务培训信息，建立3个表:

创建表

• S (S#,SN,SD,SA) S#,SN,SD,SA 分别代表学号、学员姓名、所属单位、学员年龄

create table s(
s# int,
sn varchar2(50),
sd varchar2(50),
sa int ,
constraint pk_s primary key(s#)

)

• C (C#,CN ) C#,CN 分别代表课程编号、课程名称

create table c(
c# varchar2(50),
cN varchar2(50),
constraint pk_c primary key (c#)
)

• SC ( S#,C#,G ) S#,C#,G 分别代表学号、所选修的课程编号、学习成绩

create table sc(
s# int,
c# varchar2(50),
G int,
constraint fk_s foreign key(s#) references s(s#),
constraints fk_c foreign key(c#) references c(c#)


)

插入数据

insert into s values(1,'ee','事业单位',20);
insert into s values (2,'dd','企业单位',21);
insert into s values (3,'kk','事业单位',22);
insert into s values (4,'cc','企业单位',23);
insert into s values (5,'aa','企业单位',24);
insert into s values (6,'bb','事业单位',25);

insert into sc values(1,'c2',100);
insert into sc values(2,'c3',90);
insert into sc values(3,'c4',80);
insert into sc values(4,'c5',70);
insert into sc values(5,'c1',70);


insert into c values  ('c1','税收基础');
insert into c values  ('c2','java');
insert into c values  ('c3','php');
insert into c values  ('c4','python');
insert into c values  ('c5','c++');

各张表

1, 使用标准SQL嵌套语句查询选修课程名称为’税收基础’的学员学号和姓名

select s# 学员学号,sn 姓名 from s where s# = 
(select s# from sc where sc.c# = 
(select c# from c where cn = '税收基础'))

2. 使用标准SQL嵌套语句查询选修课程编号为’C2’的学员姓名和所属单位

select sn 学员姓名 ,sd 所属单位 from s where s# = (
select s# from sc where sc.c# in(
select c# from c where c# = 'c2'))