Mysql致命错误：未捕获的错误：在布尔值上调用成员函数fetch（）

Question

<?php

$host = "localhost";

$user = "root";

$password = '';

$dbname = "rokon";

$dsn = 'mysql:host='.$host.';dbname'.$dbname;

$pdo = new PDO($dsn, $user, $password);

$query = 'SELECT * FROM customar';

$query = $pdo->query($query);

while($row = $query->fetch(PDO::FETCH_OBJ)){

    echo $row->firstname;

    echo '<br>';

}

?>

运行此代码时出现错误，错误是

致命错误：未被捕获的错误：在布尔值上调用成员函数fetch（）