求重新排这个数组

Question

<?php

$a[]=array('0','9','27','234');
$a[]=array('1','8','45','218');
echo $a0;

求$a$i;就是数组8，9的那列。来重新排这整个数组

排序函数例子
$arr=array("2772","28","20","123","0");
array_multisort($arr);
print_r($arr);
?>