Nested Query

[wreed]

Ok I have a form with a listbox that you can add too along with checkboxes.

Basically I am doing a check to see if the item in the listbox is in the table if its not then do nothing but if it is then do a delete. Now after that I do a insert with what data pertains in the check boxes....so I need to know why my submit page does nothing with this nested query run.

<?
	session_start();
	if(empty($_SESSION['user_name'])) {
		die('An error has ocurred. It may be that you have not logged in, or that your session has expired.
			Please try <a href="login.php">logging in</a> again or contact the 
			<a href="mailto:[e-mail]">system administrator</a>');
	}
	include '../connection.php';

$pid = $_POST['pid'];
$sid = $_POST['sid'];

$auddates = $_POST['auddates'];

//Check if Date is in table.
$connection = mysql_connect($host, $user, $pass) or die ("Unable to connect!");
// select database
mysql_select_db($db) or die ("Unable to select database!");

$query = "SELECT atid from msa_auditionsdatetimes WHERE atid = ".$auddates."";
$result = mysql_query($query) or die(mysql_error());
$num = mysql_num_rows($result) or die(mysql_error());

$u = 0;
while ($u < $num) {

if ($num == 0) 
  { 

  } 
  else 
  {
   $query = "DELETE FROM msa_auditionsdatetimes WHERE atid = ".$auddates."";
	echo $query;
    //execute query
    //$result = mysql_query($query2) or die ("Error in query: $query. ".mysql_error()); 
  }
++$u;
}

for($i = 1; $i < 29; $i++) {
	If (empty($_POST['audtimes_'.$i])) {

	} else {
		// create query
	    $query = "INSERT INTO msa_auditionsdatetimes (aid, atid) VALUES (".$auddates.", ".$_POST['audtimes_'.$i].")";
		echo $query;
	    // execute query
	    //$result = mysql_query($query) or die ("Error in query: $query. ".mysql_error());
	}
}
// close connection
mysql_close($connection);

//echo "<script LANGUAGE=JavaScript> self.location=\"auddates.php?pid=".$pid."&sid=".$sid."&aid=".$auddates."\";</script>";

?>

any ideas or did I lose you?

[wreed]

When I pull this code below out it works fine....
But I need to do this delete if its already in the table....unless I do an update which is more of a pain, any ideas on why?

 $query = "SELECT atid from msa_auditionsdatetimes WHERE atid = ".$auddates.""; 
    $result = mysql_query($query) or die(mysql_error()); 
    $num = mysql_num_rows($result) or die(mysql_error()); 

$u = 0; 
while ($u < $num) { 

if ($num == 0)  
  {  

  }  
  else  
  { 
   $query = "DELETE FROM msa_auditionsdatetimes WHERE atid = ".$auddates.""; 
    echo $query; 
    //execute query 
    //$result = mysql_query($query2) or die ("Error in query: $query. ".mysql_error()); 
  } 
++$u; 
} 

[Weedpacket]

You don't need to see if something is in the database before you delete it. If it's there, it will be deleted (which is what you want). If it's not there, nothing will happen (which is what you want).