Cannot add to mySQL database using XAMPP for mac - php

Question

I hello I am currently trying to add data to my user login database however for some reason my database it not being updated when I register a new user.
here is my code from user.inc.php:
<?php
//checks if username already exists in database
function user_exists($user)
{
$user = mysqli_real_escape_string($user);
$total = mysqli_query("SELECT user_id FROM user_system WHERE user_name= ('$user')");
return (mysql_result($total, 0) == '1') ? true : false;
}
//checks if username and password combo is valid
function valid_credent($user, $pass)
{
$user = mysqli_real_escape_string($user);
$pass = sha1($pass);
$total = mysqli_query("SELECT COUNT user_id FROM users
WHERE user_name = '$user' AND
user_password = '$pass' ");
return(mysql_result($total, 0) == '1') ? true : false;
}
//add user to database
function add_user($user, $pass)
{
$user = mysqli_real_escape_string(htmlentities($user));
$pass = sha1($pass);
$queryStr = "INSERT INTO users (user_name, user_password) VALUES ('$user', '$pass')";
$R = mysqli_query($mysqli,$queryStr);
}
?>
I also have warning on my register page when I try to add view errors
Warning: mysql_result() expects parameter 1 to be resource, boolean given in /Applications/XAMPP/xamppfiles/htdocs/PostalCloud/core/user.inc.php on line 8
line 8:
return (mysql_result($total, 0) == '1') ? true : false;
I have tried using "sanitize()" however that doesn't exists.
UPDATE: Still getting errors after modifying code. Here part of my register.php code and I have a init.inc.php that uses mysqli to connect to database.
<?php
include('init.inc.php');
$errors = array();
if(isset($_POST['username'], $_POST['password'], $_POST['repeatPassword']))
{
if(empty($_POST['username']))
{
$errors[] = 'The username cannot by empty. ';
}
if(empty($_POST['password']) || empty($_POST['repeatPassword']))
{
$errors[] = 'The password cannot by empty. ';
}
if($_POST['password'] !== $_POST['repeatPassword'])
{
$errors[] = 'Password verification failed. ';
}
if(user_exists($_POST['username']))
{
$errors[] = 'The username you entered is already taken. ';
}
if(empty($errors))
{
add_user($_POST['username'], $_POST['password']);
$_SESSION['username'] = htmlentities($_POST['username']);
header('Location: protected.php');
die();
}
}
?>
init.inc.php:
<?php
session_start();
$exceptions = array('register', 'login');
$page = substr(end(explode('/',$_SERVER['SCRIPT_NAME'])), 0, -4);
if(in_array($page, $exceptions) === false)
{
if(isset($_SESSION['username']) === false)
{
header('Location: login.php');
die();
}
}
$mysqli = mysqli_connect('localhost','root','', 'user_system');
$path = dirname(__FILE__);
include("{$path}/core/user.inc.php");
?>

Answer 1

The problem is that mysql_query() is returning a boolean instead of a result resource. There are two reasons this can happen:
You performed query that returns success/fail instead of a result
set (e.g. UPDATE)
Your query failed
your query contains single quotes on column names..this should be removed :
$total = mysqli_query("SELECT user_id FROM user_system WHERE user_name= '$user'");