Php的准备声明

I was following the prepared statement example on the php.net site and I cant seem to get my version to work.

$link = mysql_connect("localhost","root","mypassword") or die (mysql_error());

$query= $link->prepare("select * from users WHERE userid = ? AND password=password('?')");
$query->bindParam(1, $userid);
$query->bindParam(2, $password);
$query->execute();

if (mysql_num_rows($query)==1)
    {
        echo "Welcome, ",$userid,"
";
    }
    mysql_close($link);

I get the error: syntax error, unexpected T_VARIABLE

Change echo "Welcome, ",$userid," ";

to

echo "Welcome, " . $userid . " ";

Use mysqli_* like $link = mysqli_connect(...

Change following code

` echo "Welcome, ",$userid,"
";`

into

` echo "Welcome, " . $userid . "
";`

This is because, PHP use ‘.’ for concatenation of a string.