I there

Im using PDO and php to select table data from a MySql table on my web site

Code:
<?php
	if (isset($_GET['a']) != '')
	{
		$vehicleid = $_GET['a'];
		$select = "SELECT InvoiceNumber,InvoiceDate,Amount FROM InvoicesView WHERE VehicleId = ".$vehicleid ;
		try
		{
			$con = new PDO('mysql:host=mjt.mooo.com;dbname=MJTGarage;charset=utf8','ian','urksworks');
		}
		catch (PDOException $ex)
		{
			$error = true;
			echo $ex->getMessage();
		}
		$st = $con->prepare($select);
		$response = $st->execute();
		try
		{
		if ($response === true) 
		{	
			$titles = array('InvoiceNumber', 'InvoiceDate', 'Cost'); //<---------------- hard coded here
            $html_table = '<table border="1" cellspacing="0" cellpadding="2"><tr>';
			foreach($titles as $title)
            {
				$html_table .= "<th> $title </th>";                          
            }
            $html_table .='</tr>';
			$rows = $st->fetchALL(PDO::FETCH_ASSOC);
			foreach( $rows as $row ) 
            {
                $html_table .= '<tr>' . "\n";
                foreach( $row as $col ) 
                {
					$html_table .= '<td>' .$col. '</td>';
                }
                $html_table .= '</tr>' . "\n";
            }
			echo $html_table;
		}
		else
		{
			$response["success"] = 0;
			$response["message"] = $ex->getMessage();
			echo json_encode($response);
		}
		}
		catch (Exception $oex)
		{
			echo $oex->getMessage();
		}
		
	}
?>
this is my php script and it does work as i want.... But the bit i don't like is hard coding the titles is there no way that i can get that data from the results??

Ian