Trying to create a hyperlink

[Eggweezer]

I am pulling data from a database and displaying it in a simple table.
My goal is to figure out how to be able to click on one of the 2 table headers, and make the page reload, sorting on the column selected.

I am first of all trying to figure out to make the headers into "hyperlinks". I cannot figure it out.

Here is my code, and I would appreciate any help or advice. Thank you.

        // get results from database 
        $result = mysql_query("SELECT * FROM mytable ")  
                or die(mysql_error());   
                 
        // display data in table                
        echo "<table border='1' cellpadding='10'>"; 
        echo "<tr><th>Last Name</th><th>First Name</th></tr>"; 

        // loop through results of database query, displaying them in the table 
       	$count= 0;
	    while($row = mysql_fetch_array( $result )) { 
        ++$count;
		
	  
	  // echo out the contents of each row into a table 
	             echo "<tr>";
				 echo '<td width="100">' . $row['nameLast'] . '</td>';
				 echo '<td width="100">' . $row['nameFirst'] . '</td>';
                 echo "</tr>";   
        }  

        echo "</table>"; 
?>

[Old Pedant]

Okay, this is really 90% a PHP question and only 10% MySQL.

And I don't use PHP. So bear with me if I make a couple of PHP typos.

<!-- don't use PHP to write out large blocks of HTML -->
<!-- makes it harder to read, harder to write, and tiny bit slower -->
<table border="1"' cellpadding="10">; 
<tr>
    <th><a href="thispage.php?by=nameLast">Last Name</a></th>
    <th><a href="thispage.php?by=nameFirst">First Name</a></th>
</tr>
<?php
// make you db connection here ...

$orderby = $_GET["by"];
if ( ! isset($orderby) || ( $orderby != "nameLast" && $orderby != "nameFirst" ) ) 
{
    $orderby = "nameLast"; // or whatever default you choose
}

// get results from database 
$result = mysql_query("SELECT * FROM mytable ORDER BY $orderby ")  
                or die(mysql_error());   

... rest the same ...

[Eggweezer]

Thanks Old Pendant. I appreciate your taking the time. Makes perfect sense once someone shows you!