如何在控制器中获取codeigniter数据表值？

I am using codeigniter framework with datatables option. In this I need to add condition in the custom add column. For that I need to get value from same query to write condition. Is it possible to get value in controller itself. I need to get export_status value, and if it is 1 means, I need to hide some options from the add_column option. Eg: I need to hide the download PDF option. Because I don't know how to get value from the query to write condition. Or I can form this to view file using mRender option. Below I have given my query.

$this->datatables
    ->select("sales.id as sid, CONCAT(sales.id, ' ',sales.export_status) as chid, date, reference_no, customer_name, note, delete_status, table_name, count, inv_total, inv_discount, total_tax2, total, internal_note",FALSE);
    $this->datatables->join('order_table', 'order_table.id=sales.tableid', 'left');
    $this->datatables->from('sales'); 

    $this->datatables->add_column("Actions", 
    "<center><a href='index.php?module=sales&view=add_delivery&id=$1' title='".$this->lang->line("add_delivery_order")."' class='tip'><i class='icon-road'></i></a>
    <a href='index.php?module=sales&view=pdf&id=$1' title='".$this->lang->line("download_pdf")."' class='tip'><i class='icon-file'></i></a> 
    <a href='index.php?module=sales&view=email_invoice&id=$1' title='".$this->lang->line("email_invoice")."' class='tip'><i class='icon-envelope'></i></a></center>", "sid, internal_note")
    ->unset_column('sid')
    ->unset_column('internal_note');

Pls help me guys.Thanks in advance.