How to Allow Duplicate SKUs in WooCommerce Products

By default, WooCommerce does not permit duplicate SKUs (Stock Keeping Units) for products, and attempting to save a product with an existing SKU will result in an error. However, there are scenarios where using duplicate SKUs is necessary. In this blog post, we’ll guide you on how to allow duplicate SKUs in WooCommerce and discuss the potential implications of this change.

Why Use Duplicate SKUs?

Using duplicate SKUs can be helpful in several scenarios:

• Bundled Products: Products sold individually and as part of a bundle.
• Multi-Category Products: Products listed in multiple categories but essentially the same.
• Inventory Management: Simplifying inventory tracking by using the same SKU for similar products.

Add the Following Code:

This code disables the unique SKU check allowing duplicate SKUs. You can use this code in your child-theme or in a custom plugin.

add_filter('wc_product_has_unique_sku', '__return_false', 99);

Impact on WooCommerce Functionality

Allowing duplicate SKUs can cause certain WooCommerce features to malfunction. Here are some common issues and their solutions:

1. Shortcodes

Shortcodes such as [add_to_cart], [add_to_cart_url] and [product_page] that use the sku parameter will fetch the first product with the given SKU which may not be the intended product.

Solution: Use the product ID instead of the SKU.

2. WooCommerce REST API

Using SKUs in the WooCommerce REST API to add products to orders might not work correctly if duplicate SKUs exist. The API could add the wrong product to the order.

Solution: Use the product ID instead of the SKU.

'line_items' => array(
    array(
        'product_id' => 123,
        'quantity' => 2,
    ),
),

3. CSV Product Import

When importing products via CSV duplicate SKUs in the file will cause those products to be ignored.

Solution: Remove the SKU column from the import file or ensure SKUs are unique.

4. Product Image Matching

WooCommerce can automatically match product images by SKU, but if duplicate SKUs exist, only the first product with that SKU will have the image updated.

Solution: Ensure unique SKUs for products that need automatic image matching.

Pros and Cons of Allowing Duplicate SKUs

Pros

• Simplified Inventory Management: Using the same SKU for similar products can streamline inventory processes.
• Flexibility: Allows for more flexible product categorization and bundling.
• Consistency: Maintains consistency in SKU usage across different products.

Cons

• Inventory Confusion: Can lead to confusion in inventory management if not handled properly.
• Reporting Issues: Analytics and reports might become less accurate due to duplicate SKUs.
• Compatibility: Some third-party plugins and integrations might not support duplicate SKUs.

Conclusion

Allowing duplicate SKUs in WooCommerce can be beneficial in specific situations, but it also introduces potential challenges. By following the methods outlined in this guide, you can enable duplicate SKUs on your WooCommerce store. Be mindful of the impact on WooCommerce functionality and adopt best practices to manage your inventory effectively.