Sorter i multi-dimentionelt array

Håber du kan bruge det her til noget!
<?php
for($i=0;$i<10;$i++)
{
    $testarray[] = array(    "alfa" => rand(0,10),
                "beta" => rand(0,10),
                "gamma" => rand(0,10));
}
foreach($testarray as $value)
{
    $sortarray[] = $value["alfa"];
}

array_multisort($sortarray, $testarray);
foreach($testarray as $value)
{
    print_r($value);
    echo "<br>";
}
?>