I have ignited datatables step up and I'm stuck on a new feature I would like to add. I have 2 cells, email and phone which I would like to be hidden the code looks like this.

Code:
->edit_column('leads.email', '<span style="font-style:italic;"> Accept to View Email </span>', 'leads.email')
->edit_column('leads.phone', '<span style="font-style:italic;"> Accept to View Phone </span>', 'leads.phone');
How can I detect whether the phone is null in the database as, I need to change the message to imply there is a phone number present. Any help would be great, thanks guys.

Code:
<?php
require_once('../../../datatables/Datatables.php');
require_once('../../../Connections/datatables-connect.php');

if (!isset($_SESSION)) {
  session_start();
}

$datatables = new Datatables();  // for mysqli  =>  $datatables = new     Datatables('mysqli'); 

$datatables->connect($config);

$datatables
->select('leads.lead_id, leads.date_time, CONCAT(leads.first_name," ",leads.surname), CONCAT(leads.country," / ",leads.area), courses.course_type, leads.email, leads.phone, leads.ip_address, leads.enquiry, leads.notes')

->from('courses')

->join('leads', 'leads.lead_get_course_id = courses.course_id', 'left')
->select('start_date, price')

->join('addresses', 'courses.course_get_address_id = addresses.address_id', 'left')
->select('addresses.location_name, addresses.address_name, address, postcode, addresses.date_added, price_option, duration, duration_option, awarding_body, results_turnaround')

->join('clients', 'clients.client_id = courses.course_get_client_id', 'left')
->select('clients.client_id')

->select('leads.town_city')
->select('leads.travel_distance')

->where('checked_by_admin = "Yes" AND status = "Pending" AND clients.client_id = "'.$_SESSION['ClientID'].'"')

->unset_column('clients.client_id')

->add_column('moreinfo', '<div align="center" style="cursor:pointer"><img src="../images/details_open.png" class="buttons" alt="More Info"/></div>', 'leads.lead_id')

->add_column('approve', '<div align="center" style="cursor:pointer"><img src="../images/approve.png" class="buttons" alt="Approve" onClick="javascript:approve_link($1);"/></div>', 'leads.lead_id')

->add_column('decline', '<div align="center" style="cursor:pointer"><img src="../images/unapprove.png" class="buttons" alt="Unapprove" onClick="javascript:decline_link($1);"/></div>', 'leads.lead_id')

->edit_column('leads.email', '<span style="font-style:italic;"> Accept to View </span>', 'leads.email')
->edit_column('leads.phone null', '<span style="font-style:italic;"> Accept to View </span>', 'leads.phone');

if(isset($_POST['from_date']) && $_POST['from_date'] != '')
 $datatables->where('date_time >=', preg_replace("/([0-9]{1,2})\/([0-9]{1,2})\/([0-9]{4})/i", "$3-$2-$1", $_POST['from_date']));

if(isset($_POST['to_date']) && $_POST['to_date'] != '')
 $datatables->where('date_time <=', preg_replace("/([0-9]{1,2})\/([0-9]{1,2})\/([0-9]{4})/i", "$3-$2-$1", $_POST['to_date']));

echo $datatables->generate();

?>