<?php

  $Username=$_POST['uid'];

  $password=$_POST['password'];

$bd=new MYSQLI("localhost","root","","date")

$sql="select passsword from word where username='{$Username}'";

$result=$db->query($sql);

$attr=$result->fetch_row();

if($attr[0]==$password&&empty($password))

{echo"登录成功"}else{

echo "登录失败！";

}

?>

制作注册的代码，用PHP代码连接数据库时的代码出错