My SQL3

CREATE DATABASE colge_db;
drop DATABASE colge_db;
use colge_db;
CREATE table stu(
    rollNo int PRIMARY key,
    name VARCHAR(60),
    marks int,
    grade VARCHAR(1),
    city VARCHAR(80)
);
insert into stu
(rollNo, name , marks , grade , city)
VALUES
(100,"ALi",80,"A","Loralai"),
(200,"Sultan",90,"A","Quetta"),
(300,"Kainat",85,"A","Loralai"),
(400,"kamal",76,"B","Zhob"),
(500,"dani",64,"C","Zhob");
-- table related queries 
ALTER table stu
CHANGE name stu_name VARCHAR(80);
alter table stu
MODIFY grade varchar(1);
alter table stu
add COLUMN age int not null DEFAULT 20;
alter table stu
drop COLUMN age;
alter table stu
RENAME to student;

SELECT * from student;
-- truncate used to delete table data keep Strucher
-- drope del the table
-- delte delte the specific data,keep struchure
TRUNCATE table student;
DELETE from student
where stu_name = "sana";
drop table student;
insert into student
(rollNo, stu_name , marks , grade , city)
VALUES
(11,"sana",90,"A","Loralai"),
(12,"anam",80,"B","Qutta");
SELECT * from student;