php表名怎么更改

<?php
$serve = 'localhost:3306';
$username = 'root';
$password = 'admin123';
$dbname = 'examples';
$link = mysqli_connect($serve,$username,$password,$dbname);
mysqli_set_charset($link,'UTF-8'); // 設置數據庫字符集
$result = mysqli_query($link,'ALTER TABLE `a` RENAME TO `b`');
if($result){
 echo '更名成功';
}else{
 echo '更名失敗';
}
 ?>