请教数组如何多条件排序

$a = array(<br />
       '000-00'=>array(<br />
                                    'qty'=>20,<br />
                                    'price'=>200<br />
                                  ),<br />
       '0001-00'=>array(<br />
                                     'qty'=>10,<br />
                                    'price'=>100<br />
                                  ),<br />
      '0002-00'=>array(<br />
                                      'qty'=>30,<br />
                                     'price'=>50<br />
                                 )<br />
<br />
 );<br />
foreach($a as $k=>$v) {<br />
  $qty[] = $v['qty'];<br />
  $price[] = $v['price'];<br />
}<br />
array_multisort($qty, $price, SORT_DESC, $a);<br />
print_r($a);

Array<br />
(<br />
    [0001-00] => Array<br />
        (<br />
            [qty] => 10<br />
            [price] => 100<br />
        )<br />
<br />
    [000-00] => Array<br />
        (<br />
            [qty] => 20<br />
            [price] => 200<br />
        )<br />
<br />
    [0002-00] => Array<br />
        (<br />
            [qty] => 30<br />
            [price] => 50<br />
        )<br />
<br />
)<br />
<br />