Check permissions for user - php

Question

I am trying to make permission page thy will check if user have full access than some option allow to this person.I have table named users there i have 5 columns name user_id , username , password , email , permission
respectively .so now i am showing what i have done.
permissions.php
<?php
include('db.php');
$result=mysql_query("SELECT permission,user_id FROM users");
while($test = mysql_fetch_array($result))
{
$test['user_id'];
$test['permission'];
}
?>
For example mysql result on first row: $test['user_id'] = 1 and $test['permission'] = full .
Session result: $_SESSION['user_name'] = admin
So how can i check if this user id have permission full than do some think.
I am new on php sorry for my bad explanation.

Answer 1

<?php
include('db.php');
$result = mysql_query("SELECT permission,user_id FROM users WHERE username = '$_SESSION[user_name]'");
if(mysql_num_rows($result)){
$data = mysql_fetch_row($result); // fetch first row of result, we don't need a loop, as username should be unique
$permission = $data['permision'];
$user_id = $data['user_id'];
}else{
echo "Username not found.";
}
?>

Answer 2

if user have full permission, store in session full permission
while($test = mysql_fetch_array($result))
{
$_SESSION['permission'] = $test['permission'];
}
check if user have full permission
if($_SESSION['permission'] == full){
//do shomething
}

Answer 3

<?php
include('db.php'); // though you should look in to "PDO"
// default permission--disallowed
$allowed = false;
// get the permission for the current user (based on the username within
// your session variable). also make sure to sanitize anything that's being
// placed within a query to the database.
$query = sprintf("SELECT permission "
."FROM users "
."WHERE username = '%s'",
mysql_real_escape_string($_SESSION['user_name']));
$result = mysql_query($query);
while (($test = mysql_fetch_array($result)) !== false){
// we found the username, now check their access
$allowed = $test['permission'] == 'full';
}
// if ($allowed){
// super secret area
// } else {
// get out of here
// }