checkbox with session and include file

[nista]

Hello out there!!!
I would be grateful if you could give a hand here! I want to pass a value to a boolean column in the database (MySQL) with a checkbox. After submit button is pressed I have to show that the checkbox is still enabled, if there is such a value (boolean) in the database has already been passed or existed.

In my include file .inc there is a function:
function display_check(){

$php_self = $_SERVER['PHP_SELF'];
$reg_str = <<< EOREGSTR

<h2><strong>Referees' letters have been received</strong>
<input type="checkbox" name="checkbox1" value="1" $checked></h2><br></form>
EOREGSTR;
echo $reg_str;

}
?>

which I call in my regular php file::evilgrin:

if ($POST['submit'] == 'Submit') {
global $checkbox;
$checkbox = $GET['checkbox1'];

$query = "select * from comments where AID = $aid and SID = $sid and part = $part";
$result = mysql_query($query);
$rows = mysql_num_rows($result);



if ($rows < 1){
	if(empty($checkbox)){
		$check='NULL';
		$checked = "";
	}else {
            switch ($checkbox) 
	{
                 case "1":
                            $check = 1;
                            $checked = "checked";
                            break;
		default:
                            $check = 'NULL';
                            $checked = "";
                            break;
	}
		}
	$query = "insert into comments values
	($aid,$sid,$part,'$comments',NULL,'$check',NOW(),NULL)";
   	$result = mysql_query($query) or die ("error inserting comments");
	//echo '<h3> Comments submitted </h3>';

}else{
	if (empty ($checkbox)){
		$check='NULL';
		$checked = "";
	}else {
            switch ($checkbox) 
	{
                    case "1":
                            $check = 1;
                            $checked = "checked";
                            break;
                    default:
                            $check = 'NULL';
                            $checked = "";
                            break;
          }

Obviously something is wrong and I can not find it. Could you please share your thoughts?

Thanx a lot in advance!

[nista]

sorry I didn't paste it right. The code in my php file is here:

if ($_POST['submit'] == 'Submit') {
global $checkbox;
$checkbox = $_GET['checkbox1'];


$query = "select * from comments where AID = $aid and SID = $sid and part = $part";
$result = mysql_query($query);
$rows = mysql_num_rows($result);
echo $row['barcheck'];


if ($rows < 1){
	if(empty($checkbox)){
		$check='NULL';
		$checked = "";
	}else {
            switch ($checkbox) 
	{
                 case "1":
                            $check = 1;
                            $checked = "checked";
                            break;
		default:
                            $check = 'NULL';
                            $checked = "";
                            break;
	}
		}
	$query = "insert into comments values
	($aid,$sid,$part,'$comments',NULL,'$check',NOW(),NULL)";
   	$result = mysql_query($query) or die ("error inserting comments");
	//echo '<h3> Comments submitted </h3>';

}else{
	if (empty ($checkbox)){
		$check='NULL';
		$checked = "";
	}else {
            switch ($checkbox) 
	{
                    case "1":
                            $check = 1;
                            $checked = "checked";
                            break;
                    default:
                            $check = 'NULL';
                            $checked = "";
                            break;
          }
		}
	$query = "update comments
   	set comment = '$comments', barcheck='$check' where AID = $aid and SID = $sid and part = $part ";
   	$result = mysql_query($query) or die ("error updating comments");


}
echo $check;
echo $checked;
}

display_registry_comments($sid,$part,$status,$aid);//function to display the comments entered by registry for the specific user
display_check();

[nista]

anyone, please...!