How to Delete Orphaned WooCommerce Product Variations from Your Site

<?php

// Please make a backup of your database before running this snippet
// This snippet should only run in "Manual" mode.

global $wpdb;

$deleted_variations = $wpdb->query("DELETE o FROM {$wpdb->posts} o LEFT OUTER JOIN {$wpdb->posts} r ON o.post_parent = r.ID WHERE r.id IS null AND o.post_type = 'product_variation'");

echo "$deleted_variations variations were deleted.";