- var_dump: documentation ( source)
- array_diff: documentation ( source)
<?php
$arr1[22068] = array('ID' => 22068);
$arr1[22067] = array('ID' => 22067);
$arr2[22068] = array('ID' => 22068);
$arr2[22066] = array('ID' => 22066);
$arr = array_diff($arr1, $arr2);
var_dump($arr);