如何将mysqli代码更改为PDO？

Question

<?php

$pdo = new PDO("mysqli:host=localhost;dbname=alladin", 'root', '');
$output = '';
if(isset($_POST["query"]))
{
 $search = mysqli_real_escape_string($pdo, $_POST["query"]);
 $query = "
  SELECT * FROM orders
  WHERE orderNumber LIKE '%".$search."%'
  OR orderDate LIKE '%".$search."%' 
  OR requiredDate LIKE '%".$search."%' 
  OR status LIKE '%".$search."%' 
 ";
}
else
{

}
$result = $pdo->query($query = "SELECT * FROM orders ORDER BY orderNumber ");

我不明白如何将mysqli_real_escape_string更改为PDO。我曾尝试对PDO进行一些更改，但恐怕mysqli真正的转义字符串括号（$ pdo，$ _ POST [“ query”]）会影响我的预期结果。