create table emp
(
id int,
name varchar(25),
salary number
);
insert into emp values(18,'Piyush',25000);
insert into emp values(17,'Sujal',20000);
insert into emp values(65,'Yash',27000);
insert into emp values(61,'Sahil',30000);
insert into emp values(40,'Aayush',50000);
insert into emp values(23,'Gori',60000);
select * from emp;
select name from emp;
select id,name from emp;
alter table emp add(city varchar(25));
update emp SET city='Mumbai';
select * from emp;
update emp SET city='Ahmedabad' where id=18;
select * from emp;
create table emp1 as select * from emp;
truncate table emp;
select * from emp;
rollback;
select * from emp;
commit;
select * from emp;
drop table emp;
select * from emp;
select * from emp1;
delete from emp1 where id=61;
select * from emp1;
create view empview1 as select id,name from emp1;
select *from empview1;
update emp1 SET city='' where id=23;
select * from emp1;
select *from empview1;
create view empview2 as select id,name from emp1 where city IS NOT NULL;
select *from empview2;