코드 : 

$mysqli = mysqli_connect("db_host", "db_user", "db_pass", "db_name");

    if(mysqli_connect_errno()) {

        die("Could not connect: ".mysqli_connect_error());

    }
    /* 
        CREATE TABLE books(name VARCHAR(255),
                           isbn VARCHAR(10),
                           price FLOAT)
    */

    $bookname = "PHP";
    $bookisbn = "1234567890";
    $bookprice = 15000;

    $stmt = mysqli_prepare($mysqli, "INSERT INTO books VALUES(?, ?, ?)");

    mysqli_bind_param($stmt, "ssd", $bookname, $bookisbn, $bookprice);
    mysqli_execute($stmt);

    mysqli_stmt_close($stmt);
    mysqli_close($mysqli);