CREATE TABLE `user` (
`userid` int(11) NOT NULL default '0',
`item` varchar(100),
KEY `userid` (`userid`)
) TYPE=MyISAM;
INSERT INTO `user` VALUES (1, 'A1');
INSERT INTO `user` VALUES (1, 'A2');
INSERT INTO `user` VALUES (1, 'A3');
INSERT INTO `user` VALUES (1, 'A4');
INSERT INTO `user` VALUES (2, 'B1');
INSERT INTO `user` VALUES (2, 'B2');SET @t = 0;UPDATE `user`
SET
`userid` = IF((@t := @t+1), `userid`, `userid`)
, `item` = IF(@t = 3, 'C3', `item` )
WHERE `userid` = 1; SELECT * FROM `user`;
`userid` int(11) NOT NULL default '0',
`item` varchar(100),
KEY `userid` (`userid`)
) TYPE=MyISAM;
INSERT INTO `user` VALUES (1, 'A1');
INSERT INTO `user` VALUES (1, 'A2');
INSERT INTO `user` VALUES (1, 'A3');
INSERT INTO `user` VALUES (1, 'A4');
INSERT INTO `user` VALUES (2, 'B1');
INSERT INTO `user` VALUES (2, 'B2');SET @t = 0;UPDATE `user`
SET
`userid` = IF((@t := @t+1), `userid`, `userid`)
, `item` = IF(@t = 3, 'C3', `item` )
WHERE `userid` = 1; SELECT * FROM `user`;
正规的方法表中应该有主键的,至少也要有个唯一索引
这样才可以区分每一行
sql标准修改数据的时候根本就没有修改第几行的概念