How to use php functions in IF statement - php

Question

INTRO
I am trying to better understand my knowledge of Php and using classes to better prganise my code so this is just an exercise for a better understanding rather than a real world solution.
BRIEF
I am calling in a function from a class which I have just learnt to do but I want to know the best way to do something simple tasks like use the object in an IF statement.
SCENARIO
So for instance I am setting my classes like so:
class user
{
// Get users ID
function get_user_id()
{
global $conn;
$sql = 'SELECT id FROM user';
$result = $conn->query($sql);
if ($result->num_rows > 0) {
while ($row = $result->fetch_assoc() ){
echo $row['id'] . ', '; }
}
}
// Get users name
function get_user_name()
{
global $conn;
$sql = 'SELECT name FROM user';
$result = $conn->query($sql);
if ($result->num_rows > 0) {
while ($row = $result->fetch_assoc() ){
echo $row['name'] . ', '; }
}
}
}
$userId = new user;
$userName = new user;
I am then initializing in my classes like so:
<?php $userId->get_user_id(); ?>
<?php $userName->get_user_name(); ?>
and THEN I am wanting to performa simple task like show a user based on the value of their ID, the above will return 2 sets of results of 4 so id 1, 2, 3, 4 & Dan, Andy, Ryan, Aran
so I am performing a simple IF statement like so:
if($userId > 1){
echo $userName;
} else {
echo 'not working';
}
But it returns 'not working' - I am just wanting to better understand how to use the functions in a way that A works and B best practice.

Answer 1

It doen't look like you've understood OOP just yet.
These code examples should hopefully give you an introduction but as in other comments, read up on OOP. I struggled with it at first but keep at it!
Create your user class
This class represents a single user and the actions associated with a user, think of it as a blue print. It should only perform functions related to a user, it shouldn't keed to 'know' about anything else. For example, database functions sholud be done elsewhere.
class User {
private $id;
private $name;
function __construct($array)
{
$this->id = $array['id'];
$this->name = $array['name'];
}
function getId()
{
return $this->id;
}
function getName()
{
return $this->name;
}
}
Load all users into an array
$sql = 'SELECT * FROM user';
$result = $conn->query($sql);
$users = [];
while ($row = $result->fetch_assoc() ){
$users[] = new User($row);
}
// this array now contains all your users as User objects
var_dump($users);
// echo all user's details
foreach($users as $user) {
echo $user->getId();
echo ' - ';
echo $user->getName();
echo "\r\n";
}
Load a single user
$sql = 'SELECT * FROM user WHERE id = 1';
$result = $conn->query($sql);
if ($row = $result->fetch_assoc()) {
$user = new User($row);
} else {
exit('User ID does not exist');
}
// echo the user's ID and name
echo $user->getId();
echo ' - ';
echo $user->getName();
Resourses
Laracasts - https://laracasts.com/series/object-oriented-bootcamp-in-php
Search PHP OOP explained - https://www.google.co.uk/search?q=php+oop+explained

Answer 2

<?php
class user {
// Get users ID
function get_user_id() {
global $conn;
$data = array();
$sql = 'SELECT id FROM user';
$result = $conn->query($sql);
if ($result->num_rows > 0) {
while ($row = $result->fetch_assoc()) {
$data[] = $row['id'] . ', ';
}
}
return $data;
}
// Get users name
function get_user_name() {
global $conn;
$data = array();
$sql = 'SELECT name FROM user';
$result = $conn->query($sql);
if ($result->num_rows > 0) {
while ($row = $result->fetch_assoc()) {
$data[] = $row['name'] . ', ';
}
}
return $data;
}
}
$userId = new user;
$userName = new user;
// all user ids
$all_ids = $userId->get_user_id();
echo '<pre>';
print_r($all_ids);
// all user name
$all_name = $userId->get_user_name();
echo '<pre>';
print_r($all_name);`enter code here`
Check first response from both function after use if condition

Answer 3

You are comparing object with 1 not the value returned by function get_user_id().
So instead of
<?php $userId->get_user_id(); ?>
<?php $userName->get_user_name(); ?>
Try
<?php $id=$userId->get_user_id(); ?>
<?php $name= $userName->get_user_name(); ?>
and then put in your condition
if($id > 1){
echo $name;
} else {
echo 'not working';
}
I will suggest you to replace echo with return statement.

Answer 4

call your class as an object
$userid = user();
$username = user();
you can also try something like this
class user
{
// Get users ID
function get_user_id($id = "")
{
global $conn;
// check if id is empty or not
if(!empty($id)) {
$sql = 'SELECT id FROM users WHERE id = '.$id;
}else{
$sql = 'SELECT id FROM users';
}
$result = $conn->query($sql);
if ($result->num_rows > 0) {
while ($row = $result->fetch_assoc() ){
echo $row['id'] . ', '; }
}
}
// Get users name
function get_user_name($name = "")
{
global $conn;
// check if name is empty or not
if(!empty($name)) {
$sql = 'SELECT name FROM user WHERE name = '.$name;
}else{
$sql = 'SELECT name FROM user';
}
$result = $conn->query($sql);
if ($result->num_rows > 0) {
while ($row = $result->fetch_assoc() ){
echo $row['name'] . ', '; }
}
}
}
$userId = new user();
$userName = new user();
$userId->get_user_id(1);
$userName->get_user_name();
echo $userId;
echo $userName;
please make sure you sanitize the id and name before use

Answer 5

IN both get_user_id, get_user_name methods please
return $row = $result->fetch_assoc();
so, it will value comes in $userId, $userName and you can access it.
right now you return nothing so $user_id has null value so, it always goes in else condition.
Example
function get_user_id()
{
global $conn;
$sql = 'SELECT id FROM user';
$result = $conn->query($sql);
if ($result->num_rows > 0) {
$value = '';
while ($row = $result->fetch_assoc() ){
$value .= $row['id'] . ', ';
}
return $value;
}
}