📄 维勒斯.txt
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1、建表
学生 create table stu_choose (id int,name varchar2(10),sex varchar2(2),age integer,lid integer,score number(3,1));
老师 create table lesson (id int,name varchar2(10),credit number(1,1));
2、添加约束
主键 alter table stu_choose add constraint pk_stu_choose primary key(id);
alter table lesson add constraint pk_lesson primary key(id);
外键 alter table stu_choose add constraint fk_stu_choose foreign key(lid) references lesson (id);
check约束 alter table stu_choose add constraint ck_stu_choose check(sex in ('男','女') and age>18 and age<60 and score>0);
不为空约束 alter table lesson modify name not null;
alter table lesson modify credit not null;
savepoint p;
插入数据
insert into stu_choose (id,score) values (1,90);
insert into stu_choose (id,score) values (2,85.5);
insert into stu_choose (id,score) values (3,80.5);
insert into stu_choose (id,score) values (4,70);
insert into stu_choose (id,score) values (5,63.5);
insert into stu_choose (id,name,score) values (6,'张三',47);
insert into stu_choose (id,score) values (7,55);
查询加分仍不及格学生
select name from stu_choose where score = (select score from stu_choose group by score having (score+10)<60);
commit;
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