请问新建表时,这个 KEY 表示什么?
CREATE TABLE `users` (<br /> `id` int(11) NOT NULL auto_increment,<br /> `yhm` varchar(20) NOT NULL,<br /> `mm` varchar(50) default NULL,<br /> `wt` varchar(20) NOT NULL,<br /> PRIMARY KEY (`id`),<br /> KEY `yhm` (`yhm`)<br />) ENGINE=MyISAM
KEY `yhm` (`yhm`) ------ 请问这一句是做什么用的?
------解决方案--------------------KEY `yhm` (`yhm`) 是索引
------解决方案--------------------index 索引。
PRIMARY KEY (`id`), 主鍵
KEY `yhm` (`yhm`) 普通索引
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