WooCommerce - Filter orders based on how the order was created (admin versus natural)

gistfile1.txt

<?php

/*
Plugin Name: WooCommerce Filter by "Created Via"
Description: Filter orders based on how the order was created
Author:      GoWP
Author URI:  https://www.gowp.com
License:     GPL2
License URI: https://www.gnu.org/licenses/gpl-2.0.html
*/

add_action( 'restrict_manage_posts', 'wcfcv_restrict_manage_posts' );
function wcfcv_restrict_manage_posts() {
	if ( isset( $_REQUEST['post_type'] ) && ( 'shop_order' == $_REQUEST['post_type'] ) ) {
		?>
		<select name="created-via">
			<option value="">Created via...</option>
			<option value="checkout">Checkout</option>
			<option value="other">Other</option>
		</select>
		<?php
	}
}

add_filter( 'parse_query', 'wcfcv_parse_query' );
function wcfcv_parse_query( $query ) {
	if (
		is_admin()
		&& isset( $_REQUEST['post_type'] ) && ( 'shop_order' == $_REQUEST['post_type'] )
		&& isset( $_REQUEST['created-via'] ) && ! empty( $_REQUEST['created-via'] ) && ( $value = $_REQUEST['created-via'] )
	) {
		$compare = ( 'other' == $value ) ? "NOT EXISTS" : $value;
		$meta_query = array(
			array(
				'key' => '_created_via',
				'value' => $value,
				'compare' => $compare
			)
		);
		$query->set( 'meta_query', $meta_query );
	}
	return $query;
}