create unique slug in php mysql

$slug = '';
$slug = preg_replace('/[^a-z0-9]+/i', '-', trim(strtolower($_POST["business_title"])));

 $query = "SELECT `listing_slug` FROM `listing` WHERE listing_slug LIKE '$slug%'";
  $slug_result=mysqli_query($con,$query);
  $slug_num=mysqli_num_rows($slug_result);
  if($slug_num > 0)
  {
 while ($row = mysqli_fetch_assoc($slug_result)) {
     $data[] = $row['listing_slug'];
    }

if(in_array($slug, $data))
   {
    $count = 0;
    while( in_array( ($slug . '-' . ++$count ), $data) );
    $slug = $slug . '-' . $count;
   } 
 }