Example

Lets say I have the 3 tables below Customer, Business and Invoice.  Notice that Customer and Business have the same columns.

Customer [id, name, phone]
Business [id, name, phone]
Invoice [id, business, customer, description]

A normal SQL SELECT statement for this would be

SELECT c.name, c.phone, b.name, b.phone, i.description
FROM Customer c, Business b, Invoice i
WHERE c.id=i.customer AND b.id=i.business

This would output the following columns.

MySql - RESULT [name, phone, name, phone, description]
PHP - RESULT[name, phone, description]

Notice how it has name and phone twice on the MySql but when PHP looks at it as an array it has it only once.  Well we need to be able to use the other data from this statement.  To do this we will add a simple AS statement for the duplicate column names.

Example

SELECT c.name AS cname, c.phone AS cphone, b.name, b.phone, i.description
FROM Customer c, Business b, Invoice i
WHERE c.id=i.customer AND b.id=i.business

RESULT

MySql - RESULT [cname, cphone, name, phone, description]
PHP - RESULT[cname, cphone, name, phone, description]

Take a look at the first 2 columns now.  Just adding the AS statement allowed the column to have different names that you can process.