Spectacula

interconnectit

This plug-in provides you with more relevant search results than are currently 
available to the normal WordPress search and it should also do so with less of a 
performance hit on the db than the normal WordPress search. We use the MySQL 
commands MATCH () AGAINST () as opposed to WordPress’ use of LIKE to do our 
queries which are not as heavy on the db. The only issue we have with “match 
against” is that we need an index on the columns we intend to search on.

Spectacu.la Advanced Search

Changes the Wordpress search queries to provide more relevant results more efficiently and with options to influence the results.

mattsgarage

The search functionality in woocommerce doesn’t search by sku by default.
This simple plugin adds this functionality search facility of your site, in both the public site and admin panel
Just install and activate – no config required.
Tested with Woocommerce 1.5.6, 2.0.7, 2.0.18, 2.2.4, 2.2.10, 3.4.4, 4.0.1 and 4.2.0
See the <a href="http://www.mattyl.co.uk/2012/12/11/woocommerce-plugin-to-search-products-by-sku/" title="accompanying blog post" rel="nofollow ugc">Accompanying blog post</a> for more information.

Search by SKU for Woocommerce

Extend the search functionality of woocommerce to include searching of sku

Spectacu.la Advanced Search vs Search by SKU for Woocommerce