I want to display data from database by clicking button in same page

I want to display data from database by clicking button in same page. I have a table in my database. fields are sl,category,desc. when I click a button then it show particular field data that's my expectation. here is my code

<?php
include("connect.php");
$sql = "SELECT * FROM content WHERE category = 'word'";
$result = mysqli_query($con,$sql);
if (isset($sl)) {
    $sl= $_GET["sl"];
}

?>
//////////////////////
<?php

    while($row_tbl = mysqli_fetch_array($result))
                {
 ?>
   <a class="btn btn-primary" href="word.php?sl=$row_tbl[sl]" role="button"> <?php echo $row_tbl['type'] ?> </a> <br>

  <?php
      }
   ?>
//////////// display section
   <?php 
         if (isset($sl)) { 
        $sql2 = "SELECT * FROM content WHERE sl = '$sl'";
        $result2 = mysqli_query($con,$sql2);
        $row_tbl2 = mysqli_fetch_array($result2);
        echo $row_tbl2['desc'];
             }
        ?>

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