how to use if not exists while inserting a row mysql

Question

The thing that i want to do is to check if there is a same row and if not to insert a new row to the table.

In that case, how can i use if not exists ?

Answer 1

INSERT INTO `facebook` (`ID`,`fb_id`,`label_id`,`page_ids`,`token`) 
SELECT NULL, '". $session['id'] ."', '$id', '', '". $access_token ."'
FROM DUAL
WHERE NOT EXISTS (SELECT 'x' FROM facebook WHERE label_id = '$id')

I think FROM DUAL is optional, but I'm an Oracle guy. :)