insert into university_info values(10003,'Fudan',1001,600);
insert into university_info values(10004,'HaGongDa',1001,601);
insert into university_info values(10005,'BeijingLG',1001,590);
insert into university_info values(20001,'YanShan',1002,519);
insert into university_info values(20002,'HBFarmUni',1002,431);
insert into university_info values(20003,'YNDX',1002,497);
insert into university_info values(20004,'BFXY',1002,561);
insert into university_info values(20005,'TSWL',1002,500);
insert into university_info values(10011,'TsingHua',1003,623);
insert into university_info values(10012,'BeijingUni',1003,617);
insert into university_info values(10013,'Fudan',1003,585);
insert into university_info values(10014,'ZhejiangUn',1003,601);
insert into university_info values(10015,'BeijingRA',1003,580);
insert into university_info values(20011,'YanShan',1004,519);
insert into university_info values(20012,'HBFarmUni',1004,431);
insert into university_info values(20013,'YNDX',1004,497);
insert into university_info values(20014,'BFXY',1004,561);
insert into university_info values(20015,'TSWL',1004,500);
insert into university_info values(10021,'YanShan',1005,420);
insert into university_info values(10022,'HBFarmUni',1005,431);
insert into university_info values(10023,'TsingHua',1005,527);
insert into university_info values(10031,'YanShan',1006,330);
insert into university_info values(10032,'HBFarmUni',1006,359);
insert into university_info values(10033,'TsingHua',1006,575);
4. 建立学生考试成绩表（stu_grade）
create table stu_grade (
stu_num number(10) primary key,
branch varchar2(3) check(branch in('A','S','SP','AR')),
grade_mat number(4,1) check(grade_mat<=150 and grade_mat>=0),
grade_che number(4,1) check(grade_che<=150 and grade_che>=0),
grade_eng number(4,1) check(grade_eng<=150 and grade_eng>=0),
grade_inte number(4,1) check(grade_inte<=300 and grade_inte>=0)
);
insert into stu_grade values (2012100201,'S',139,114,98,251);
insert into stu_grade values (2012100202,'S',79,96,81,212);
insert into stu_grade values (2012100203,'S',112.5,88,149,229);
insert into stu_grade values (2012100204,'S',87,94,82,181);
insert into stu_grade values (2012100205,'S',76,90,67,101);
insert into stu_grade values (2012100206,'S',138,141,150,281);
insert into stu_grade values (2012100207,'S',88,94,123,61);
insert into stu_grade values (2012100208,'S',97,42,80,119);
insert into stu_grade values (2012100209,'S',39.5,24,48.5,62);
insert into stu_grade values (2012100210,'S',110,80,82,180.5);
insert into stu_grade values (2012100211,'S',97,88,109,200.5);
insert into stu_grade values (2012100212,'S',138,74,28,281);
insert into stu_grade values (2012211101,'A',112,138,143,201);
insert into stu_grade values (2012211102,'A',97,124,138,219);
insert into stu_grade values (2012211103,'A',72,64,98,123);
insert into stu_grade values (2012211104,'A',139,144,150,257);
insert into stu_grade values (2012
