Add GTIN to WooCommerce

add-gtin-to-woocommerce.php

<?php
/**
 * @snippet       Adds a column for the new GTIN input field on Products so when you export the column shows
 * @author        Serafin Tech
 * @compatible    WooCommerce 9+
 * @website       https://serafintech.io
 */

// Add the GTIN/UPC/EAN/ISBN to the export column names
add_filter('woocommerce_product_export_column_names', 'add_custom_gtin_export_column');
function add_custom_gtin_export_column($columns) {
    // Add a new column for GTIN/UPC/EAN/ISBN
    $columns['global_unique_id'] = 'GTIN/UPC/EAN/ISBN';
    return $columns;
}

// Add the GTIN/UPC/EAN/ISBN data to the export rows
add_filter('woocommerce_product_export_product_row', 'add_custom_gtin_export_row', 10, 3);
function add_custom_gtin_export_row($row, $product, $product_id) {
    // Get the GTIN/UPC/EAN/ISBN value from the product meta
    $gtin_value = get_post_meta($product_id, '_global_unique_id', true);

    // Add the value to the row in the 'global_unique_id' column
    $row['global_unique_id'] = !empty($gtin_value) ? $gtin_value : '';  // Fallback for missing values

    return $row;
}