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CREATE TABLE `user` (
  `id` int(5) unsigned NOT NULL AUTO_INCREMENT,
  `name` varchar(10) DEFAULT NULL,
  `password` varchar(10) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=MyISAM AUTO_INCREMENT=4 DEFAULT CHARSET=latin1
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1 name1 123456
2 name2 123456
3 name3 123456
4 name4  NULL
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£¨1£©select count(*) from `user`
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£¨3£©select count(password) from `user`
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mysql> select CONCAT('My', 'S', 'QL');
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