MySQL INDEX

What is Index?

 How to work Index in mysql:

Syntax:

Guidelines of Index :

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);

INDEX Examples

SELECT * FROM students
WHERE dob > "1999-01-01";

/* create index*/
CREATE INDEX studdob ON students (dob);

/* show index */
SHOW INDEX FROM students;

/* delete index */
DROP INDEX studdob ON students;