PRACTICA

create table alumno(
idalumno char(4) primary key,
paterno varchar(20),
materno varchar(20),
nombre varchar(20));
insert into alumno values('0001','Quispe','Rivas','Juan');
insert into alumno values('0002','Soto','Castro','Luis');
insert into alumno values('0003','Rivas','Quino','Ana');
insert into alumno values('0004','Castro','Rojas','Maria');
create table curso(
idcurso char(5) primary key,
curso varchar(20));
insert into curso values('MA100','MATEMATICA');
insert into curso values('FI100','FISICA');
insert into curso values('QU100','QUIMICA');
insert into curso values('FI101','FILOSOFIA');
create table nota (
idalumno char(4),
idcurso char(5),
nota numeric);
insert into nota values('0001','MA100',12);
insert into nota values('0001','FI100',14);
insert into nota values('0001','QU100',08);
insert into nota values('0001','FI101',16);
insert into nota values('0002','MA100',11);
insert into nota values('0002','FI100',08);
insert into nota values('0002','QU100',09);
insert into nota values('0002','FI101',10);
insert into nota values('0003','MA100',17);
insert into nota values('0003','FI100',13);
insert into nota values('0003','QU100',18);
insert into nota values('0003','FI101',19);
insert into nota values('0004','MA100',14);
insert into nota values('0004','FI100',15);
insert into nota values('0004','QU100',13);
insert into nota values('0004','FI101',15);