CREATE TABLE `test` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`last_no` int(11) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=12 DEFAULT CHARSET=utf8 COLLATE=utf8_bin
SELECT
b.id,
b.curr,
b.pre,
(b.curr - b.pre) AS diff
FROM
(
SELECT
a.`id` AS id,
a.last_no AS curr,
@a.last_no AS pre,
@a.last_no:= a.last_no
FROM test a,(SELECT @a.last_no:=0)r
)b