如何在PHP的下拉列表中分组结果数？

As an example I have 19 rows in the database, how do i make it so my drop down list print 10, 20, etc as opposed to 1, 2, 3, 4, 5 etc. My code below currently print 1 to 20 rather than 10, 20.

$num_rows   = mysql_num_rows($page_name_qry);
$total_num_page = round($num_rows/10)*10;

for ($counter=1; $counter<=$total_num_page; $counter++){
    $pagenumber = $counter;
    print '<option value="'.$pagenumber.'">'.$pagenumber.'</option>';
}

Current the result shows:

<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
...

But I am hoping to see:

<option value="10">10</option>
<option value="20">20</option>

Thanks

How about

$total_num_page = ceil($num_rows / 10) * 10;

for ($counter = 10; $counter <= $total_num_page; $counter += 10) {
    print '<option value="' . $counter . '">' . $counter . '</option>';
}

With your code you get only 9 rows in your dropdown list. do you really want this? if not i.e you want total 19 rows as you have then you can try with the following :

$num_rows   = mysql_num_rows($page_name_qry);

for ($counter=1; $counter<=$num_rows; $counter++){
    $pagenumber = $counter*10;
    print '<option value="'.$pagenumber.'">'.$pagenumber.'</option>';
}