Adding user_id into Session mysql

Question

I am trying to failing to figure out how to add my user_id from my database to a session like my username is. I would like it so when I log in I can called the session to call the user id posts based on the username used to log in.

How do I do this?

my login php:

<?php

session_start();

$connect = mysql_connect( "localhost", "user", "pass") or die('Database could not connect');
$select = mysql_select_db( "database", $connect) or die('Database could not select');

if (isset($_POST['submit'])) {
    $username = $_POST['username'];
    $password = $_POST['password'];
    chckusername($username, $password);
}

function chckusername($username, $password){

    $check = "SELECT * FROM users WHERE username='$username'";
    $check_q = mysql_query($check) or die("<div class='loginmsg'>Error on checking Username<div>");

    if (mysql_num_rows($check_q) == 1) {
        chcklogin($username, $password);
    }
    else{
        echo "<div id='loginmsg'>Wrong Username</div>";
    }
}

function chcklogin($username, $password){

    $login = "SELECT * FROM users WHERE username='$username'  and password='$password' ";
    $login_q = mysql_query($login) or die('Error on checking Username and Password');



print_r($lohin_q);

    if (mysql_num_rows($login_q) == 1){



        header('Location: http://ct6014-williams.studentsites.glos.ac.uk/pages-multi-page/home.php');        
        $_SESSION['username'] = $username;
        $_SESSION['user_id'] = $userid; //this is where I want to store the user id

    }
    else {
        echo "<div id='loginmsg'>Wrong Password </div>"; 

    }
}
?>

on home.php:

<?php echo "Your username is " . $_SESSION["username"] . "."; ?>    
     <?php echo "Your id is " . $_SESSION["user_id"] . "."; ?>

database names:

user_id , username , user_first_name , user_last_name , user_email , password , user_reg_date

EDIT:

Ahh, I forgot to say, I have used include( 'login.php' ); which created the session when I logged in as a user. The first username session echos but I cannot seem to figure out hoe to set up the user_id session

Answer 1

In chcklogin() function, use mysql_fetch_array() function to fetch the row from the result set and assign the required user data to $_SESSION . So change your if (mysql_num_rows($login_q) == 1){ ... block in the following way,

if (mysql_num_rows($login_q) == 1){
    $row = mysql_fetch_array($login_q);
    $_SESSION['username'] = $row['username'];
    $_SESSION['user_id'] = $row['user_id'];
    header('Location: http://ct6014-williams.studentsites.glos.ac.uk/pages-multi-page/home.php'); 
    exit();
} else {
    echo "<div id='loginmsg'>Wrong Password </div>"; 

}

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Sidenote: Don't use mysql_* functions, they are deprecated as of PHP 5.5 and are removed altogether in PHP 7.0. Use mysqli or pdo instead. And this is why you shouldn't use mysql_* functions .