Get data from mysql db by slug url not id – SEO

Im facing problem in getting data from mysql db by slug url. When i get data from id it works fine. I substituted urlslug also but no use.

Im trying to change my site article url(s)

mysite.com/public.php?id=12    to    mysite.com/public/google-search

My table:

+----+---------------+---------+------------------------------------+
| id | title         | article |   urlslug  VARCHAR 500 NULL        |
+----+---------------+---------+------------------------------------+
| 12 | google search | xxxxxxx |   google-search                    |
| 13 | bing yahoo    | xxxxxxx |   bing-yahoo                       |
| 14 | friendly seo  | xxxxxxx |   friendly-seo                     |
+-------------------------------------------------------------------+

code to get data by id:

$id = $_GET['id'];
$id = mysqli_real_escape_string($conn,$id);
$query = "SELECT * FROM `table` WHERE `id`='" . $id . "'";
$result = mysqli_query($conn,$query);

while($row = mysqli_fetch_array($result)) {
echo ($row['title']);
echo ($row['article']);    }

Please help. Thanks.