3

    function createSite() {

        if ($_GET['q'] == 'info' or !isset($_GET['q'])) {
            return createMainPage();
        } else if ($_GET['q'] == 'buy') {
            return "Infp";
        } else if ($_GET['q'] == 'about') {
            return "Info about company";
        } else {
            return "Error 404";
        }
    }

<?php
    // Create info about product
    function createMainPage() {
        $database = mysqli_connect(
            "localhost", "root",
            "", "module3"
        );

        if (mysqli_connect_errno()) {
            echo "Не подключено!", mysqli_connect_errno(), ": ", mysqli_connect_error();
            exit();
        }

        $query = "SELECT * FROM info";
        $data = mysqli_fetch_all(
            mysqli_query($database, $query),
            MYSQLI_ASSOC
        );



        return $result;
    }