PHP mySQLi examples

<?php

    if (isset($_GET['username']))
    {
        $username=$_GET['username'];
        if ($username === '')
        {
            exit;
        }

        $host = 'localhost';
        $user = 'user';
        $pass = 'pass';
        $db = 'db';
        $table = 'forum_cookies';

        $mysqli = new mysqli($host,$user,$pass,$db);
        if ($mysqli->connect_errno)
        {
            printf("Connect failed: (%s) %s\n", $mysqli->errno, $mysqli->connect_error);
            exit;
        }


        //get one row example:
        if ($result = $mysqli->prepare("SELECT * FROM $table WHERE username=?"))
        {
            $result->bind_param('s', $username);
            $result->execute();
            $result->bind_result($ri_username, $ri_date, $ri_user_id, $ri_p_cookies);
            $result->fetch();
            //do stuff with $ri_username, $ri_date, $ri_user_id, $ri_p_cookies here
            $result->close();
        }
        else
        {
            printf("Query failed: (%s) %s\n", $mysqli->errno, $mysqli->error);
            exit;
        }

        //or:
        if ($result = $mysqli->prepare("SELECT * FROM $table WHERE username=?"))
        {
            $result->bind_param('s', $username);
            $result->execute();
            $result->bind_result($ri_username, $ri_date, $ri_user_id, $ri_p_cookies);
            $result->fetch();
        }
        else
        {
            printf("Query failed: (%s) %s\n", $mysqli->errno, $mysqli->error);
            exit;
        }
        //do stuff with $ri_username, $ri_date, $ri_user_id, $ri_p_cookies here
        $result->close();


        //get more than one row example:
        if ($result = $mysqli->prepare("SELECT * FROM $table WHERE sender=? OR receiver=?"))
        {
            $result->bind_param('ss', $username, $username);
            $result->execute();
            $result->bind_result($r_username, $r_target_username, $isupvote, $date);
            $no_results=true;
            while ($result->fetch())
            {
                //do stuff with $r_username, $r_target_username, $isupvote, $date
                //in the next while passtrough, a new row will be loaded into those variables
                //or if you want to keep them all, load them into an array (there's a better function for this though, that does it all in one go)
                $no_results=false;
            }
            $result->close();
        }
        else
        {
            printf("Query failed: (%s) %s\n", $mysqli->errno, $mysqli->error);
            exit;
        }


        //insert one row example
        //with additional error checks (which have been omited in the above SELECT queries)
        //you can include them if you want, but it's kinda superfluous, I just put them here as an example
        if ($result = $mysqli->prepare("INSERT INTO $table VALUES (?,?,?,?)"))
        {
            if (!$result->bind_param('ssss', $username, $target_username, $isupvote, $date)) {
                printf("Binding parameters failed: (%s) %s\n", $stmt->errno, $stmt->error);
                exit;
            }
            if (!$result->execute()) {
                printf("Execute failed: (%s) %s\n", $stmt->errno, $stmt->error);
                exit;
            }
            $result->close();
        }
        else
        {
            printf("Query failed: (%s) %s\n", $mysqli->errno, $mysqli->error);
            exit;
        }

        //then after the last query:
        $mysqli->close();
    }



?>