issue in session variables - php

Question

I am new to php.
I want to use form data that are sent through <form method="POST" action="formdata.php"> to formdata.php be used in another file called main.php. For this I ucerated session variables in formdata.php
Hers's my code in formdata.php
<?php
session_start();
include_once("connect.php");
$n=$_POST['name'];
$p=$_POST['password'];
$sql=mysql_query**strong text**("SELECT * FROM member WHERE `userName`='$n' AND `password`='$p'");
if(mysql_num_rows($sql)==1){
$_SESSION['user']=mysql_fetch_array(mysql_query("SELECT * FROM member WHERE `userName`='$n' AND `password`='$p'"));
if($_SESSION['user']){
$user=$_SESSION['user'];
$_SESSION['userN']="$user(['userName'])";;
$_SESSION['level']="$user(['level'])";
//header("location:mainPage.php");
echo $user['level'];
echo $_SESSION['level'];
}
}
else{
echo "invalid user name or password" ;
}
?>
But when I echo $user['level'];
echo $_SESSION['level']; all I get printed is 3Array(['level']). Here echo $user['level'] gives the desired out put 3, but echo $_SESSION['level'] gives an array as Array(['level']). What can I do to make it print 3?
My next question is I want to use this level value in another php file (main.php). I lerant that session variables are global. So can I use $user['level'] or should I use $_SESSION['level']. In main.php I want to check the condition
if($user['level'] == 3) {
echo "level 3 user";
}

Answer 1

The issue is this line: $_SESSION['userN']="$user(['userName'])";;
You're setting $_SESSION['userN'] equal to whatever $user is in string form which is Array, and (['username']).
Why are you even setting userN? $_SESSION should already contain the user in question, and you can just retrieve it anywhere to get the contents.
This should be all you need:
<?php
session_start();
include_once("connect.php");
$n=mysql_escape_string($_POST['name']);
$p=mysql_escape_string($_POST['password']);
$sql = mysql_query("SELECT * FROM member WHERE `userName`='$n' AND `password`='$p'");
if(mysql_num_rows($sql)==1)
{
//You can reuse the original $sql here. No need to run another query.
$_SESSION['user']=mysql_fetch_array($sql);
//If mysql_num_rows($sql) returns 1, $_SESSION['user'] should always be equal to a user array (Which is true).
header("location:mainPage.php");
}
else{
echo "invalid user name or password" ;
}
?>
On the other page (mainPage.php), just use session_start(), and check to see what is inside $_SESSION. This script should give you a jump start:
<?php
session_start();
print_r($_SESSION);
//This will get the level you're looking for
$level = $_SESSION['user']['level'];
?>
It should contain the user/level and any other information you need.