easyui下datagrid嵌套显示相关文件

<?php include 'conn.php'; $itemid = mysql_real_escape_string($_REQUEST['itemid']); $rs = mysql_query("select * from lineitem where itemid='$itemid'"); $items = array(); while($row = mysql_fetch_object($rs)){ array_push($items, $row); } echo json_encode($items); ?>