WooCommerce: Save Item SKU to Order Item Meta for Historical Reference

This question came from Stack Overflow asking, for warranty purposes, how to save a product’s SKU to the order item meta for future discovery.

The problem is that when a product still exists in an installation the SKU is available for reporting, etc. But once that product is deleted the SKU reference is now gone. Saving it to the order item meta is a good idea.

• WooCommerce

add_action( 'woocommerce_add_order_item_meta', 'majemedia_save_item_sku_order_itemmeta', 10, 3 );
function majemedia_save_item_sku_order_itemmeta( $item_id, $values, $cart_item_key ) {

        $item_sku  =  get_post_meta( $values[ 'product_id' ], '_sku', true );

        wc_add_order_item_meta( $item_id, 'sku', $item_sku , false );

}

The above will work only in cases where a product has been added to the cart that doesn’t have any variations. The following will not only save the parent SKU but also the variation SKU to the item meta.

add_action( 'woocommerce_add_order_item_meta', 'majemedia_save_item_sku_order_itemmeta', 10, 3 );
function majemedia_save_item_sku_order_itemmeta( $item_id, $values, $cart_item_key ) {

        $item_sku  =  get_post_meta( $values[ 'product_id' ], '_sku', true );

        $item_has_variation  =  ( ! empty( $values[ 'variation_id' ] ) ? true : false );

        if( $item_has_variation ) {

                wc_add_order_item_meta( $item_id, 'parent_sku', $item_sku, false );

                $variation_sku  =  get_post_meta( $values[ 'variation_id' ], '_sku', true );
                wc_add_order_item_meta( $item_id, 'variation_sku', $variation_sku, false );

        }
        else {

                wc_add_order_item_meta( $item_id, 'sku', $item_sku , false );

        }

}