<?php
$server_host = "host";
$server_username = "username";
$server_password = "password";
$server_dbName = "data base name";

$player_username = $_POST ["usernamePost"];
$player_password = $_POST ["passwordPost"];
$player_displayName = $_POST ["displayNamePost"];

$conn = new mysqli ($server_host, $server_username, $server_password, $server_dbName);

if (!$conn) {
    echo "Error connecting to the server.";
}

$query_code = "SELECT Username FROM users WHERE Username = '{$_POST[usernamePost]}'";
$result_login = mysqli_query ($conn,$query_code);
$anything_found = mysqli_num_rows ($result_login);

if ($anything_found > 0) {
echo "An account with this username or display name already exsists, please choose another.";
}

if ($anything_found <= 0) {

$sql = "INSERT INTO users (Username, Password, Display_Name)
        VALUES ('".$player_username."','".$player_password."','".$player_displayName."')";
$result = mysqli_query ($conn,$sql);
if ($result) {
    echo "You may now login.";
}
if (!$result) {
    echo "Error.";
}