Ordenando + de 1 Filtro

if (isset($_GET['country'])){
 switch ($_GET['country']){
 case br:
 $where = "WHERE `flag` = br.png";
 break;
	case pl:
 $where = "WHERE `flag` = pl.png";
 break;
	case us:
 $where = "WHERE `flag` = us.png";
 break;
	case us:
 $where = "WHERE `flag` = us.png";
 break;
	case pt:
 $where = "WHERE `flag` = pt.png";
 break;
}

} else { $where = NULL; }

if (isset($_GET['order'])){
 switch ($_GET['order']){
 case id_asc:
 $sql = "SELECT * FROM list $where ORDER BY id ASC";
 break;
 case name_asc:
 $sql = "SELECT * FROM list $where ORDER BY name ASC";
 break;
	case ip_asc:
 $sql = "SELECT * FROM list $where ORDER BY ip ASC";
 break;
	case exp_asc:
 $sql = "SELECT * FROM list $where ORDER BY exp ASC";
 break;
	case client_asc:
 $sql = "SELECT * FROM list $where ORDER BY client ASC";
 break;
 case name_desc:
 $sql = "SELECT * FROM list $where ORDER BY name DESC";
 break;
	case ip_desc:
 $sql = "SELECT * FROM list $where ORDER BY ip DESC";
 break;
	case exp_desc:
 $sql = "SELECT * FROM list $where ORDER BY exp DESC";
 break;
	case client_desc:
 $sql = "SELECT * FROM list $where ORDER BY client DESC";
 break;
 }
} else { $sql = "SELECT * FROM list $where ORDER BY id ASC LIMIT $inicio, $qnt"; }

Ele da erro aqui, quando eu uso '?country=': [na linha do while]

$query = mysql_query($sql);
while ($sql = mysql_fetch_array ($query) ) {

Erro:

Warning: mysql_fetch_array() expects parameter 1 to be resource, boolean given in /home/tibiabot/public_html/otlist/includes/lista.php on line 87

Minhas dúvidas:

1. Ta certo o modo que eu usei para filtrar?

2. Porque tá dando o erro e como eu resolvo?

Valeu!!