在PHP中查找子数组匹配

I have an array in the format:

我有一个格式的数组:

array (
   '1' => array (
      'id' => '2',
      'qty' => '4'
   ),
   '2' => array (
      'id' => '1',
      'qty' => '1'
   ),
   '3' => array (
      'id' => '2',
      'qty' => '3'
   ),
   '4' => array (
      'id' => '4',
      'qty' => '6'
   )
);
a