php或者javascript注册界面如何判断用户名和邮箱是否已存在,存在则报错...答:sql="INSERT INTO `user`(`id`, `username`, `password`, `email`, `idgroup`, `lastdate`) VALUES ('','$_POST[username]','$_POST[password]','$_POST[email]','$_POST[idgroup]',now())"; $sql1="select * from user where username='$_POST[username]'";...
PHP如何判断用户名是否在某个数据库字段里面?答:例 先将数据库用户表读出来 读到一个二维数组中 <?php$name = "赵五";$data =array(array('id'=>'1','name'=>"张三",'sex'=>"女",'age'=>'12'),array('id'=>'2','name'=>"李四",'sex'=>"男",'age'=>'16'),array('id'=>'3','name'=>"王二",'sex'=>"...