Get a list of all WooCommerce orders that have fees negative applied.

fee-orders.php

<?php

/**
 * Get a list of all WooCommerce orders that have negative fees applied. 
 * Installation: Just put it in your root folder (where wp-config.php is). Execute the file /fee-orders.php.
 * 
 */

require_once "wp-load.php";

function get_all_orders_with_negative_fees() {

	global $wpdb, $table_prefix;

	$query = "SELECT items.order_id FROM `" . $table_prefix . "woocommerce_order_itemmeta` itemmeta INNER JOIN `" . $table_prefix . "woocommerce_order_items` items ON items.order_item_id = itemmeta.order_item_id WHERE itemmeta.meta_key = '_line_subtotal' AND itemmeta.meta_value < 0";

	$results = $wpdb->get_results($query, OBJECT);

	return $results;
}

$orders = get_all_orders_with_negative_fees();

?>

<ul>

<?php
foreach($orders as $order) :
	
	$edit_url = sprintf('/wp-admin/post.php?post=%d&action=edit', $order->order_id);

	?>

	<li><a href="<?php echo $edit_url; ?>" target="_blank">Edit order #<?php echo $order->order_id ?></a></li>

<?php endforeach ?>
</ul>