JOIN BETWEEN 2 TABLES WITH DIFFERENT ID COUNTING

[Roberto B.]

Starting from 2 same structure tables A and B

CREATE TABLE A (
`id` mediumint(9) NOT NULL AUTO_INCREMENT,
`NAME` varchar(255) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=16384 DEFAULT CHARSET=utf8 ROW_FORMAT=COMPACT;

but in A and B relative id to the same value of NAME can be different.

How can i get id of a table (let's say A) starting from each value of NAME in B?
I was using JOIN in many ways but getting always null results.
For example:

SELECT a.id FROM A
JOIN B
ON A.NAME = B.NAME;