Admin filter for product SKU?

I used a plugin “WooCommerce Filter Orders by Product” and modified their search by ID, added a get_post_meta(), and now have the ability to filter products by ID.

Plugin: https://en-ca.wordpress.org/plugins/woocommerce-filter-orders-by-product/

Modified code:

    // Display dropdown
    function foa_product_filter_in_order(){
        global $typenow, $wpdb;

        if ( 'shop_order' != $typenow ) {
            return;
        }

        $sql="SELECT ID,post_title FROM $wpdb->posts WHERE post_type="product" AND post_status="publish"";
        $all_posts = $wpdb->get_results($sql, ARRAY_A);

        $values = array();

        foreach ($all_posts as $all_post) {
            $values[$all_post['ID']] = get_post_meta($all_post['ID'], '_sku', true);
        }



        ?>
        <select name="foa_order_product_filter">
        <option value=""><?php _e('All products', 'foa'); ?></option>
        <?php
            $current_v = isset($_GET['foa_order_product_filter'])? $_GET['foa_order_product_filter']:'';
            foreach ($values as $label) {
                printf
                    (
                        '<option value="%s"%s>%s</option>',
                        $value,
                        $value == $current_v? ' selected="selected"':'',
                        $label
                    );
                }
        ?>
        </select>
        <?php
    }