create table customer
(
customer_id int,
first_name char(10),
last_name char(10),
age int,
country char(10)
) ;
insert into customer values(1,' Dev dh','Gohil', 19,'India') ;
insert into customer values(2,'Ansh','suthar', 12,'USA') ;
insert into customer values(3,'Vansh','Parmar', 15,'china') ;
insert into customer values(4,'sujal','waghela', 15,'srilanka') ;
insert into customer values(5,'gaurav','chauhan', 23,'srilanka') ;
select * from customer;
alter table customer add constraint custprimary primary key(customer_id);
create table orders
(
order_id int,
item char(10),
amount char(10),
customer_id int references customer(customer_id)
) ;
insert into orders values(1,'keyboard', 400,4);
insert into orders values(2,'mouse', 300,4);
insert into orders values(3,'monitor', 12000,3);
insert into orders values(4,'keyboard', 400,1);
insert into orders values(5,'mousepad', 250,2);
select * from orders;
select * from orders where customer_id in (select customer_id from customer where first_name='Dev') ;
update customer set first_name=UPPER(first_name) ;
select * from customer;
select REVERSE(first_name) from customer where customer_id=5;
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