Javascript-форум - Вывод из БД с использованием ООП, PDO и namespace

Я сделал поиск по базе, он работает, сделал некоторые проверки, скажите, что не так?

index.php

<?php
header('Content-Type: text/html; charset=utf-8');
error_reporting(-1);
 
require_once 'App/db.php';
 
use App\classes\Db as Db;
 
$con = new Db();
 
try{
    $sth3 = $con->myPrepare();
}
 
catch(PDOException $e){
    echo $e->getMessage();
    exit();
}
 
$searchForm = [];
 
if(!empty($_GET['author']) || !empty($_GET['name']) || !empty($_GET['isbn'])){
 
    $searchForm[] = trim(htmlspecialchars($_GET['name']));
    $searchForm[] = trim(htmlspecialchars($_GET['author']));
    $searchForm[] = trim(htmlspecialchars($_GET['isbn']));
   
    $need = '';
    $needSql = '';
   
    if(!empty($searchForm[0])){
        $need = $searchForm[0];
        $needSql = 'name';
    }
    if(!empty($searchForm[1])){
        $need = $searchForm[1];
        $needSql = 'author';
    }
    if(!empty($searchForm[2])){
        $need = $searchForm[2];
        $needSql = 'isbn';
    }
   
    $sth = $con->SearchPrepare($needSql, $need);
 
    require_once 'html.php';
   
    while($bookName = $sth->fetch()){
        if($bookName['name']){
       
            echo '<tr>';
                echo'<td>' . $bookName['name'] . '</td>';
                echo'<td>' . $bookName['author'] . '</td>';
                echo'<td>' . $bookName['year'] . '</td>';
                echo'<td>' . $bookName['genre'] . '</td>';
                echo'<td>' . $bookName['isbn'] . '</td>';
            echo '</tr>';
           
        }
    }
    echo '</table>';
echo '</body>';
echo '</html>';
}
 
else{
require_once 'html.php';
 
    foreach($sth3 as $book){
        echo '<tr>';
            echo'<td>' . $book['name'] . '</td>';
            echo'<td>' . $book['author'] . '</td>';
            echo'<td>' . $book['year'] . '</td>';
            echo'<td>' . $book['genre'] . '</td>';
            echo'<td>' . $book['isbn'] . '</td>';
        echo '</tr>';
    }
}
    echo '</table>';
echo '</body>';
echo '</html>';

db.php

<?php
namespace App\classes;
 
class Db{
    protected $pdo;
    private $sql = 'SELECT * FROM `books`';
    protected $statement;
   
    public function __construct(){
        try{
            $this->pdo = new \PDO('mysql:host=localhost; dbname=dz; charset=utf8', 'root', '');
            $this->pdo->setAttribute(\PDO::ATTR_ERRMODE, \PDO::ERRMODE_EXCEPTION);
        }
        catch(PDOException $e){
            echo $e->getMessage();
        }
    }
   
    public function getSql(){
        return $this->sql;
    }
   
    public function myPrepare(){
        $this->statement = $this->pdo->prepare($this->sql);
        $res = $this->statement->execute();
       
        if(false !== $res){
            $books = $this->statement->fetchAll();
            return $books;
        }
        return [];
    }
   
    public function SearchPrepare($needSql, $need){
        $sth2 = $this->pdo->prepare('SELECT * FROM `books` WHERE `'.$needSql.'` LIKE :search');
        $sth2->execute([':search'=>'%'.$need.'%%']);
        return $sth2;
    }
   
}

html.php

<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <style>
        h1{margin:0; margin-bottom: 21px;}
        form{margin-bottom: 1em;}
        table{
            border-spacing: 0;
            border-collapse: collapse;
        }
        .gray{background: #eee;}
       table td, table th{
            border: 1px solid #ccc;
           padding: 5px;
        }
    </style>
</head>
    <body>
   
<h1>Библиотека успешного человека</h1>
<form>
    <input type="text" name="isbn" placeholder="ISBN">
    <input type="text" name="name" placeholder="Название книги">
    <input type="text" name="author" placeholder="Автор книги">
    <input type="submit" value="Поиск">
</form>
     <table>
    <tr class="gray">
        <th>Название</th>
        <th>Автор</th>
        <th>Год выпуска</th>
        <th>Жанр</th>
        <th>ISBN</th>
    </tr>