PHP & MYSQL: Select from where id=$id - php

Question

So I'm making a usergroup function that allows me to block off pages to lower user levels. This is my function for grabbing info:
function grab_info($id, $requested_info){
$id = $_SESSION['user_id'];
$requested_info = $requested_info;
$con = new mysqli('localhost', 'root', '', 'login');
if ($con->connect_errno >0){
die("Handle your connection error here");
}
$sql = "SELECT * FROM `users` WHERE `id` = $id";
if (!$result = $con->query($sql)) {
die("There as a query error for some reason handle your query error");
}
while($row = $result-fetch_assoc()){
$info = $row[$requested_info];
return $info;
}
}
Right here:
$sql = "SELECT * FROM `users` WHERE `id` = $id";
if (!$result = $con->query($sql)) {
die("There as a query error for some reason handle your query error");
}
is where something is going wrong. This is my method for grabbing the info:
$id = $_SESSION['user_id'];
$rank = grab_info($id, 'rank');//Gets rank from our id
$meets = can_access($rank, 4, true);//We're saying our user has a rank of 1 to access this page you need a rank of 3 and only 3 hence strict
if ($meets == false){//user cant access page
header("Location: index.php");
die();
}
Basically, it just keeps giving me the "There as a query error for some reason handle your query error" and I'm stuck. New to php so sorry if it's messy.

Answer 1

Using prepared statements and cast the variable as an integer.
$stmt = $con->prepare("SELECT * FROM `users` WHERE `id` = ?");
$stmt->bind_param("i",$id);
$id = (int) $_SESSION['user_id'];
$stmt->execute();
$result = $stmt->get_result();

Answer 2

Check to make sure that $id is actually set. If it's null that will cause your query to explode.

Answer 3

$sql = "SELECT * FROM `users` WHERE `id`='{$id}'";
Try this :)

Answer 4

$query=mysql_query("SELECT * FROM user WHERE user_email='$user_email');

Answer 5

Please try this:
function grab_info($id, $requested_info){
$id = $_SESSION['user_id'];
$requested_info = $requested_info;
$con = new mysqli('localhost', 'root', '', 'login');
if ($con->connect_errno >0){
die("Handle your connection error here");
}
$sql = "SELECT * FROM users WHERE id =". $id;
if (!$result = $con->query($sql)) {
die("There as a query error for some reason handle your query error");
}
while($row = $result->fetch_assoc()){
$info = $row;
return $info;
}
}