Need Help with a MySQL Query

Hello everyone, 

I am finding difficulties to make a mysql query based on this idea:

Computer Science 
 - Dan Vick
 - Harry Jones

Marketing
 - John Doe

Business
 - Leo Rodriguez

IT
 - Tim Ben


Could someone help me?
Thank you! 

PHP Code:

$query = $this->db->select('department,fullname')->from('employees')->order_by('department,fullname')->get();
$offset = '';
foreach($query->result() as $row) {
   if ($row->department != $offset) {
     echo '<h3>' . $row->department . '</h3>';
     $offset = $row->department;
   }
   echo '- ' . $row->fullname . '<br />';
} 


PHP Code:

$query = $this->db->select('department,fullname')->from('employees')->order_by('department,fullname')->get();
$offset = '';
foreach($query->result() as $row) {
   if ($row->department != $offset) {
     echo '<h3>' . $row->department . '</h3>';
     $offset = $row->department;
   }
   echo '- ' . $row->fullname . '<br />';
} 


Works as intended, many thanks Wouter60.