问Unable to AES_DECRYPT after AES_ENCRYPT in mysql

EN

CREATE  TABLE `user` (
`id` BIGINT UNSIGNED NOT NULL AUTO_INCREMENT ,
`first_name` VARBINARY(100) NULL ,
`address` VARBINARY(200) NOT NULL ,
PRIMARY KEY (`id`))
ENGINE = InnoDB
DEFAULT CHARACTER SET = utf8
COLLATE = utf8_general_ci;

INSERT into user (first_name, address) VALUES (AES_ENCRYPT('Obama', 'usa2010'),AES_ENCRYPT('Obama', 'usa2010'));

SELECT AES_DECRYPT(first_name, 'usa2010'), AES_DECRYPT(address, 'usa2010') from user;