function my_get_ticket_booked_spaces( $booked_spaces, $EM_Ticket ){
	global $wpdb;
	$table_name   = $wpdb->prefix.'em_tickets_bookings';
	$booked_spaces = $wpdb->get_var('SELECT SUM(ticket_booking_spaces) AS booked_space FROM '.$table_name.' WHERE ticket_id='. absint($EM_Ticket->ticket_id) .' GROUP BY ticket_id');	
	return $booked_spaces;
}
add_filter('em_ticket_get_booked_spaces', 'my_get_ticket_booked_spaces', 100, 2 );