create table people(
employee_id number(9),
first_name varchar2(15),
last_name varchar2(20),
email varchar2(25),
constraint pk_people primary key (employee_id)
);
insert into people
values (1, 'Tom', 'Kyte', 'YourName@q.com');
insert into people
values (2, 'Sean', 'Viper', 'sdillon@q.com');
insert into people
values (3, 'Christopher', 'Beck', 'clbeck@q.com');
select * from people;
alter table people drop column first_name;
alter table people drop column last_name;
select * from user_unused_col_tabs;
ALTER TABLE people DROP UNUSED COLUMNS;
drop table people;