01

use 20200198db;
set foreign_key_checks = 0;
drop table if exists Students;
set foreign_key_checks  = 1;

CREATE TABLE Students
(
  ROLL_NO int,
  NAME varchar(20),
  SUBJECT varchar(20)
);

DESC Students;

INSERT INTO Students VALUES (198, "Thahir", "OOPS");

INSERT INTO Students (ROLL_NO, NAME, SUBJECT) VALUES
(198, "Ahmed", "DSA"),
(231, "Ram", "DSA");

SELECT * FROM Students;
SELECT ROLL_NO FROM Students;
SELECT * FROM Students ORDER BY ROLL_NO;
SELECT * FROM Students ORDER BY ROLL_NO desc;

ALTER TABLE Students ADD (AGE int,COUNTRY varchar(40));
ALTER TABLE Students DROP COLUMN AGE;
ALTER TABLE Students MODIFY COUNTRY varchar(20);

alter table table_name drop primary key, add primary key(k1, k2, k3);

DELETE FROM Students WHERE NAME = 'Ram';
DELETE FROM Students WHERE AGE = 20;

DROP TABLE Students;