We can give

alias

to tables or table columns. In this example table column

first_name

will be displayed as

student_name

SELECT 
    id,
    first_name AS student_name
FROM students

The keyword

AS

is optional, but it's better to use it, because the query is much more readable. The following query returns the same result

SELECT 
    id,
    first_name student_name
FROM students

We can use

alias

in

ORDER BY

clause to order the result

SELECT *, price * quantity AS total
FROM `orders` 
ORDER BY total DESC

If

alias

is given to table, column of the table can be accessed by the alias followed by

.

SELECT 
    s.id,
    s.first_name
FROM `students` s

In

SELF JOIN

alias is required, because MySQL needs to treat the tables as different tables

SELECT  
    s1.*,
    s2.first_name
FROM `students` s1
JOIN `students` s2 ON s2.santa_id = s1.id

quotes

or backticks can be used in alias. Possible options: single quote

'

, double quote

"

or backtick

 ` 

SELECT
    id,
    first_name AS 'student_name'
FROM 
    students

Advantage of using

quotes

is that we can use space separated names in alias

SELECT 
    first_name, 
    last_name, 
    (points + 10) * 2 AS 'points calculated'
FROM students