<?php
            include('includes/login_connection.php');

        //  $query = "select * from personal_details, course_codes";
            $query = "select p.usn, p.name, p.sem, p.year, cg.cur_cgpa, c.cc1, c.cc2, c.cc3, c.cc4, c.cc5, c.cc6, c.cc7, c.cc8, c.cc9 from personal_details p, course_codes c, cgpa_details cg where p.usn = c.usn AND p.usn = cg.usn order by p.usn";

            $run = mysql_query($query) or die($query."<br/><br/>".mysql_error());
            $num=mysql_numrows($run);
            echo "No. of registered students: $num";
            while($row = mysql_fetch_assoc($run)){


                echo "<tr>";
                echo "<td>" . $row['usn'] . " </td>";
                echo "<td>" . $row['name'] . " </td>";
                echo "<td>" . $row['sem'] . " </td>";
                echo "<td>" . $row['year'] . " </td>";
                echo "<td>" . $row['cur_cgpa'] . " </td>";
                echo "<td>" . $row['cc1'] . " </td>";
                echo "<td>" . $row['cc2'] . " </td>";
                echo "<td>" . $row['cc3'] . " </td>";
                echo "<td>" . $row['cc4'] . " </td>";
                echo "<td>" . $row['cc5'] . " </td>";
                echo "<td>" . $row['cc6'] . " </td>";
                echo "<td>" . $row['cc7'] . " </td>";
                echo "<td>" . $row['cc8'] . " </td>";
                echo "<td>" . $row['cc9'] . " </td>";
                echo "</tr>";

    //      echo "</table>";


            }
            mysql_close($bd);

?>

<table border='1' align="center" style="font-size:14px" width="95%" cellspacing="3" class="db_table" >

<tr class="db_table_tr" >
 <th class="db_table_th" >USN</th>
 <th class="db_table_th" >Name</th>
 <th class="db_table_th" >Sem</th>
 <th class="db_table_th" >Year</th>
 <th class="db_table_th" >CGPA</th>
 <th class="db_table_th" >Subject-1</th>
 <th class="db_table_th" >Subject-2</th>
 <th class="db_table_th" >Subject-3</th>
 <th class="db_table_th" >Subject-4</th>
 <th class="db_table_th" >Subject-5</th>
 <th class="db_table_th" >Subject-6</th>
 <th class="db_table_th" >Subject-7</th>
 <th class="db_table_th" >Subject-8</th>
 <th class="db_table_th" >Subject-9</th>
</tr></table>

echo "<td>" . $row['usn'] . " </td>";

echo "<td> <a href='http://somedomain/somepath/usn_handler.php?usn='" . $row['usn'] .
     "' >" . $row['usn'] . "<a/> </td>";

<?php
 $link = $row['usn'];
?>
<td><a href="filename.php?usn=<?php echo $link; ?>"><?php echo $link; ?></a></td>