PHP排序一个关联数组 - PHP sort an associative array

我有一个这样的数组。我需要按[0][amount]值对国家(数组键)进行排序。

Array
(
    [Germany] => Array
        (
            [0] => Array
                (
                    [amount] => 50
                    [count] => 1
                )
        )
    [Poland] => Array
        (
            [0] => Array
                (
                    [amount] => 80
                    [count] => 2
                )
        )
)

结果应该是波兰第一，德国第二。对PHP有什么概念吗?

我明白了…

$amount = array();
foreach ($originArray as $key => $value)
{
        $amount[$key] = $value[0]['amount'];
}
array_multisort($amount, SORT_DESC, $originArray);