Using input checkboxes with a database - php

Question

So I'm trying to help a friend out by writing his guild an attendance tracker for raiding and whatnot. Right now my concept is to do a select * from the user column, and make a checkbox for each user, assuming that person showed up to raid, it would pass a "1" through the form, and their raid attendance would be incremented by 1. On the users page the overall attendance would be calculated as (raidAtt / raidsTotal)*100 (since joining).
My issue right now is that I don't really know how to get all this information passed using a single loop...
Right now my code is something like this:
<form action="raidattend.php" method="post">
<?php
mysql_connect("$database",$username,$password);
#mysql_select_db($database) or die( "Unable to select database");
$query="SELECT * FROM attend WHERE UserName = $v_member ORDER BY date desc";
$result=mysql_query($query);
$num=mysql_numrows($result);
mysql_close();
?>
<table>
<tr>
<th>Member</th>
<th>Attended?</th>
</tr>
<?php
$i=0;
while ($i < $num) {
$f1=mysql_result($result,$i,"UserName");
}
<tr>
<td><?php echo $f1; ?></td><td input type="checkbox" checked value="1">
And that's where I ran into issues. I'm not sure how to pass each user and the result of the checkbox back to the database. Once I understand how to do that it's just as simple as incrementing, but I'm pretty lost.
Thanks for any help!
Edit: To clarify, what I'm unsure of is how to break it up so each member gets updated, I understand that I need to use a submit and all that.
Edit 2: Stray }

Answer 1

You should change your checkbox so that they all have the same name (ie name="member[]"). This way, when you submit your form, all of the checked members will be in $_POST['member']. Then, just loop through $_POST['member'] and update your table.
<td><?php echo $f1; ?><td> <input type="checkbox" name="member[]" value=<?php echo "'$f1'"; ?> /></td>
This should give you the list of checkboxes with the names of the members that attended.
Here is a quick overview of how to do the update:
1.Loop through $_POST['member'] and increment the amount that person has attended :
foreach($_POST['member'] as $member)
{
mysql_query("update table_name set attended=(attended+1) where username='$member'");
}
2.After you update each member that attended, do an update on the entire table to increment the total number of raids that have happened:
mssql_query("update table_name set total=(total+1)");

Answer 2

on form:
<input type=checkbox name=selected[] value='" . $f1 . "'>
on raidattend.php:
$selected=$_POST['selected'];
while (list ($key,$val) = #each ($selected)) {
//$val will hold the username
}