alter.sql

create database college;
use college;

create table student(
rollno int primary key,
name varchar(50),
marks int not null,
grade varchar(1),
city varchar(20));

insert into student(rollno, full_name, marks, grade, city)
values
(101, "anil", 78, "C", "Pune"),
(102,"bhumika", 93, "A", "Mumbai"),
(103, "chetan", 85, "B", "Mumbai"),
(104, "dhruv", 96, "A", "Delhi"),
(105, "emanuel", 12, "F", "Delhi"),
(106, "farah", 82, "B", "Delhi");

select * from student;

alter table student
add column age int;
alter table student
drop column age;

alter table student
add column age int not null default 19;
alter table student
modify column age varchar(2);

insert into student(rollno, name, marks,stu_age) values (107, "garghi",68,100);

alter table student
change age stu_age INT;
alter table student drop column stu_Age;

alter table student
rename to stu;

truncate table student;

alter table student change name full_name varchar(50);
delete from student
where marks<80;
SET SQL_SAFE_UPDATES=0;
alter table student
drop column grade;