Small PHP profile page issue

[Alex12345]

So far, I have managed to create a register, login and welcome page with PHP. I'm now focusing on a creating a profile page. I'm wondering, first of all, how I can have every page on my site display "Welcome, " .$username. Do I have to insert a cookie write session_start(); on top of each page to do that, or is there an easier way?

And for the actual profile page, how can I make it display data from the database? I know it's fairly simple, but it doesn't work so far. I've tried something really simple, but lines 8, 10 and 14 are off. Thanks a lot for any help

BASICALLY, I'm asking how I can fetch data from my table just for the user that's logged in and display it.

<?php 
session_start();

$link = mysql_connect('localhost','root','1234') or die('Cant connect to database');
mysql_select_db('youtube');
	
$username=$_COOKIE['username'];
$username=$_COOKIE['password'];

$query = mysql_query("SELECT username FROM user WHERE username='$username' 
AND password='$password'")
or die(mysql_error());

echo "Welcome, " . $username . ".";
echo $email;
//echo a bunch of other stuff, such as the user's age, real name and so forth

if (!isset($_SESSION['username']))
{
	header('location: login.php');
}
?>

[Alex12345]

Please forget the previous code. I've changed it to this and have NO idea why it's not working (it's not posting the full name):

<?php 
session_start();
include "config.php";
	
echo "Welcome, " . $_SESSION['username'];
$result = mysql_query("SELECT username FROM user WHERE username='$username'")
or die(mysql_error());
$row=mysql_fetch_array($result);

echo "Hi, " . $row['full_name'];

if (!isset($_SESSION['username']))
{
	header('location: login.php');
}
?>
<p>Would you like to edit your <a href="editprofile.php">profile?</a><p>

Thanks again!

[phorce]

Noticed a few things.

<?php 
session_start();
include "config.php";

if (!isset($_SESSION['username']))
{
	header('location: login.php');
}

echo "Welcome, " . $_SESSION['username'];
$result = mysql_query("SELECT username, full_name FROM user WHERE username='$username'")
or die(mysql_error());
$row=mysql_fetch_array($result);

echo "Hi, " . $row['full_name']; // You haven't selected "full_name"

?>
<p>Would you like to edit your <a href="editprofile.php">profile?</a><p>

What error(s) do you have? I'm guessing that the row "full_name" is storing two attributes inside i.e. "Joe Bloggs" this is bad database design!

[phorce]

Also if you're doing profiles (I'm guessing you want other people to view these profiles?)

You'll need to write another script that handles it, there are many ways but:

www.yoursite.com/user/view_profile.php?id={user_id}

<?php

     $id = $_GET['id'];

     echo "Viewing profile for, $id";
?>

Then you can write sql select statements that selects all the information depending on the user id.. Look at like SQL injections so it's a lot more secure!