i am working on a social networking project and i have built the skeleton of my site using mysql functions but i read all over the place online that i should instead be using mysqli or PDO, the problem is i have been looking for a while and i cant find a decent mysqli resource. i can convert the server login page over to work with mysqli and i have tested the connection and it works with this statement
PHP Code:
$db = new mysqli($dbhost$dbuser$dbpass$dbname);
if (
mysqli_connect_errno()) {
    
printf("Can't connect to MySQL Server. Errorcode: %s\n"mysqli_connect_error());
    exit;
}
$sql="SELECT * FROM members";

if (
$result=mysqli_query($db,$sql)) {
    
// Return the number of rows in result set
    
$rowcount=mysqli_num_rows($result);
    
printf("Result set has %d rows.\n",$rowcount);
    
// Free result set
    
mysqli_free_result($result);

it returns it correctly without issue but those same function in the code below are giving me trouble.
PHP Code:
require_once 'header.php';
echo 
"<div class='main'><h3>Please enter your details to log in</h3>";
$error $user $pass "";

if (isset(
$_POST['user'])) {
    
$user sanitizeString($_POST['user']);
    
$pass sanitizeString($_POST['pass']);

    if (
$user == "" || $pass == "") {
        
$error "Not all fields were entered<br />";
    } else {
        
$query "SELECT user,pass FROM members
                WHERE user='
$user' AND pass='$pass'";

        if (
mysqli_num_rows(mysqli_query($db$query))  == 0) {
            
$error "<span class='error'>Username/Password invalid</span><br /><br />";
        } else {
            
$_SESSION['user'] = $user;
            
$_SESSION['pass'] = $pass;
            die(
"You are now logged in. Please <a href='members.php?view=$user'>" .
            
"click here</a> to continue. <br /><br />");
        
        }
    }
}

echo <<<_END
<form method='post' action='login.php'>$error
<span class='fieldname'>Username</span><input type='text' maxlength='16' name='user' value='
$user' /> <br />
<span class='fieldname'>Password</span><input type='password' maxlength='16' name='pass' value='
$pass' />
_END;