Hi,,
If you have a unique id you can give it in check box value...
<?php $conn=mysqli_connect("localhost","","","test"); echo"connected"; $query="SELECT * FROM student ORDER BY roll_no"; $res=mysqli_query($conn,$query); $row=(mysqli_fetch_array($res,MYSQLI_ASSOC)); echo "roll_no".$row['roll_no']; echo "subject".$row['subject']; echo "marks".$row['marks']."<br/>"; echo "<table border='1'>"; echo "<tr> <th>ROLL_NO</th> <th>SUBJECT</th> <th>MARKS</th>
<th>Select</th> </tr>"; while($row = mysqli_fetch_array($res,MYSQL_ASSOC))
{ echo"<tr><td>"; echo $row['roll_no']; echo "</td><td>"; echo $row['subject']; echo "</td><td>"; echo $row['marks']; echo "</td>"; echo "<td><input type=\"checkbox\" name=\"name\" value=\"$row[id]\"></td>"; echo "</tr>"; } echo "</table>"; ?>