array (size=10)
  \'comment 0\' =>
    array (size=2)
      \'comment_id\' => string \'22\' (length=2)
      \'parent_of\' => string \'0\' (length=1)
  \'comment 1\' =>
    array (size=2)
      \'comment_id\' => string \'23\' (length=2)
      \'parent_of\' => string \'0\' (length=1)
  \'comment 2\' =>
    array (size=2)
      \'comment_id\' => string \'24\' (length=2)
      \'parent_of\' => string \'0\' (length=1)
  \'comment 3\' =>
    array (size=2)
      \'comment_id\' => string \'25\' (length=2)
      \'parent_of\' => string \'0\' (length=1)
  \'comment 4\' =>
    array (size=2)
      \'comment_id\' => string \'26\' (length=2)
      \'parent_of\' => string \'24\' (length=2)
  \'comment 5\' =>
    array (size=2)
      \'comment_id\' => string \'27\' (length=2)
      \'parent_of\' => string \'22\' (length=2)
  \'comment 6\' =>
    array (size=2)
      \'comment_id\' => string \'28\' (length=2)
      \'parent_of\' => string \'0\' (length=1)
  \'comment 7\' =>
    array (size=2)
      \'comment_id\' => string \'29\' (length=2)
      \'parent_of\' => string \'25\' (length=2)
  \'comment 8\' =>
    array (size=2)
      \'comment_id\' => string \'30\' (length=2)
      \'parent_of\' => string \'29\' (length=2)
  \'comment 9\' =>
    array (size=2)
      \'comment_id\' => string \'31\' (length=2)
      \'parent_of\' => string \'27\' (length=2)

主要输出：22、23、24、25、26、27、28、29、30、31

正确顺序：22 -> 27->31，23，24 -> 26、，25 -> 29->30，28