Получить массив данных после store_result() в mysqli

$sql = "SELECT `id` FROM `table` WHERE `email` = ? ";
$stmt = $mysqli->prepare($sql);
$stmt->bind_param('s', $email);
if($stmt->execute()){
    $stmt->store_result();
    if($stmt->num_rows){
        $result = $stmt->get_result();
        $res = $result->fetch_assoc();
        echo res['id'];
    }
}
$stmt->close();
$mysqli->close();

$sql = "SELECT `id` FROM `table` WHERE `email` = ? ";
$stmt = $mysqli->prepare($sql);
$stmt->bind_param('s', $email);
if($stmt->execute()){
    $result = $stmt->get_result();
    if($result->num_rows){
    $res = $result->fetch_assoc();
        echo res['id'];
    }
}
$stmt->close();
$mysqli->close();

<?php
$mysqli = new mysqli('localhost', 'root', '', 'test');
 
$id = 14;
 
$sql = 'SELECT `product_id` FROM `product` WHERE `product_id` = ?';
$stmt = $mysqli->prepare($sql);
$stmt->bind_param('s', $id);
 
if($stmt->execute())
{
    # Вариант 1
    $result = $stmt->get_result();
 
    if($result->num_rows)
    {
        $row = $result->fetch_assoc();
        echo $row['product_id'];
    }
    else
        echo 'Не найдено.';
    
    # Вариант 2
    $stmt->store_result();
    
    if($stmt->num_rows)
    {
        $stmt->bind_result($result_id);
        $stmt->fetch();
        echo $result_id;
    }
    else
        echo 'Не найдено.';
}