UPDATE: As it turns out, WooCommerce has added built-in support for the bulk editing of variations. While editing your product, after having added one or more variations, the “Add Variation” drop-down at the top of the Variations tab also includes a number of bulk edit options; you can set both regular and sale prices or modify either, increasing or decreasing by a percentage or set amount, for example.
Assuming you’re not using a very old version of WooCommerce, you can use the above and ignore the rest of this article.
We’ll make use of the
(Aug 20, 2015) As of WooCommerce version 2.4 the contents of the Variations tab are not loaded initially, so we’ve added a version check that waits until Variations have been loaded via AJAX before triggering the addition of our links.
This can be added as a stand-alone plugin (recommended) or to the
functions.php of your active (child) theme.
(March 13, 2018) Per a request, we’ve updated this code/plugin to duplicate this functionality for the sale price as well as the regular price.