如何修改codeigniter查询结果

Question

我正在构建一个输出xml文件的脚本但我无法从单个查询生成所有数据，因为描述可能来自各种来源。到目前为止，我有：

// Select the products
$query = $this->db->select('id,sku,name,image')
        ->from('products')
        ->get();



// !!! Here's where I need help - I need to loop through the results and run
// another query based on the ID which will pull a description from
// a number of possible sources and then add the resulting description into
// the main $query object so it can still use xml_from_result()




// Load the Database Utilities
$this->load->dbutil();

// Configure the xml structure
$config = array (
    'root'    => 'root',
    'element' => 'element', 
    'newline' => "\n", 
    'tab'    => "\t"
  );

// Output the xml doc
header('Content-type: text/xml');
echo $this->dbutil->xml_from_result($query, $config);

我可以通过首先执行$ query-＆gt; result（）来获取我需要的数据但是我不能再使用$ query与xml_from_result（）。任何帮助将不胜感激。