DBから同業種・同じ市場の銘柄を抽出する

select * from table where で条件を記載します。

$code = empty($_GET["code"])? 'null' : $_GET["code"];

$dsn = "mysql:dbname=equity;host=localhost";
$user = "hoge";
$password = "hogehoge";
 
try {
    $dbh = new PDO($dsn, $user, $password);
} catch (PDOException $e){
    print('connection failed:'.$e->getMessage());
} 


$sql = "select * from lists where code = $code";
$stmt = $dbh->query($sql);

$result = $stmt->fetch(PDO::FETCH_ASSOC);
$sector = $result['sector'];
$market = $result['market'];

echo "<b>".$result['name']. "</b>(".$code.") ";
echo $result['sector'] ." ".$result['market']. "<br><br>";
echo "同業種の銘柄(".$sector.")"."<br>";

$sql2 = "select * from lists where market = '$market' AND sector = '$sector' and code != $code";
$stmt2 = $dbh->query($sql2);
while($result = $stmt2->fetch(PDO::FETCH_ASSOC)){
	    echo $result["code"]." ".$result["name"]. "<br>";
}