MySQL ALTER

 How to Modify tables in MySql:

Features of MySql Alter command:

Alter Syntax:

Code:

CREATE TABLE personal(

id INT NOT NULL,

name VARCHAR(50) NOT NULL,

    percentage INT NOT NULL,

age INT NOT NULL,

gender VARCHAR(1) NOT NULL,

city INT NOT NULL,

    courses INT NOT NULL,

    PRIMARY KEY (id),

FOREIGN KEY (city) REFERENCES City (cid),

    FOREIGN KEY (courses) REFERENCES Courses (course_id)  

);

INSERT INTO personal(id,name,percentage,age,gender,city,courses)

VALUES

(1,"Aqib","45","13","M",1,1),

(2,"Khadija","56","21","F",2,2),

(3,"Salman Khan","62","20","M",1,1),

(4,"Aqeela","47","18","F",3,1),

(5,"Saqib","74","22","M",1,3),

(6,"Abraham","64","21","M",2,2),

(7,"Shahid","52","20","M",1,3);

ALTER Examples

ALTER TABLE students
ADD Email varchar(255);

ALTER TABLE students
MODIFY Email varchar(255)
AFTER name;

ALTER TABLE students
MODIFY Email INT(10);

ALTER TABLE students
ADD UNIQUE (Email);

ALTER TABLE students
CHANGE Email Email_id carchar(255);

ALTER TABLE students
DROP COLUMN Email_id;

ALTER TABLE students
RENAME studentss;

ALTER TABLE studentss
RENAME students;

ALTER TABLE courses
AUTO_INCREMENT = 4;