Bug found, caused Google Product Feed to fail

When updating prices using this plugin, even though the sales price was completely left alone (no value), when saving the row the value of the sale price gets change from empty to NULL.

This has no effect on the product when using WooCommerce, but when using the WooCommerce Google Product Feed plugin, the affected products are excluded from the feed.

To fix this I had to run the following SQL:

UPDATE wp_postmeta
SET meta_value = “”
WHERE meta_key = “_sale_price”
and meta_value is null

Can you please fix your plugin to prevent this from happening?

Thanks.