php help

Main PHP
<?php
    require 'steamauth/steamauth.php';
    require 'connection.php';
    $Credits = 0;
    if(isset($_SESSION['steamid'])){
    include  ('steamauth/userInfo.php');
    $steamid         = $steamprofile['steamid'];
    $SteamName       = $steamprofile['personaname'];
    $isAdmin = false;
    $sql_table = "users";
    $sql_Admin_table = "betterbot_administrators";
    $sql = "SELECT * FROM $sql_table WHERE steamId = $steamid;";
    $sql_insert_data = mysqli_query($conn,"INSERT INTO $sql_table (steamId, steam_Name)
    VALUES ('$steamid', '$SteamName');");
    $results = $conn->query($sql);
        if ($results->num_rows > 0) {
    // output data of each row
            while($row = $results->fetch_assoc()) {
            echo "id: " . $row["id"]. " - steam_Name: " . $row["steam_Name"]. "- steamId: " . $row["steamId"].  "- isAdmin: " . $row["isAdmin"]."<br>";
                if ($row["isAdmin"] == "true"){
                $isAdmin = true;
                    if ($isAdmin === true){
                    $admin =$row["isAdmin"];
                    $sql = "SELECT * FROM $sql_Admin_table WHERE steamId = $steamid;";
                    $result = $conn->query($sql);
                        if ($result == false) {
                            $sql = mysqli_query($conn,"INSERT INTO $sql_Admin_table (`steamId`, `steam_Name`, `isAdmin`) VALUES ('$steamid', '$SteamName', '$admin');");
                            if ($conn->query($sql) == true){
                            }else{

                            }
                        }else{

                        }
                    }
                }else{
                $sql = mysqli_query($conn,"INSERT INTO $sql_Admin_table (SteamId, SteamName) VALUES ('$steamid', '$SteamName');");
                    if ($conn->query($sql) == TRUE)
                    {
                        echo "New record created successfully";
                    } else {
                        echo "Error: " . $sql . "<br>" . $conn->error;
                    }
                }
            }
        }
        else
        {

        }
        mysqli_close($conn);
    }
?>
Connection Php
<?php
$servername = "localhost";
$username = "root";
$password = "";
$dbname = "users";

// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}
echo "Connected successfully";
?>