When in admin backend there is a small search box besides the posts list which adds the ?s= var to the posts query.
i.e. /wp-admin/[url removed, login to view]
Wordpress uses it to add "post_title LIKE %TERM% or post_content LIKE %TERM%".
I need a small plugin which changes that behaviour so I can specify one custom field (from postmeta) which is also searched for.
The query should then be "post_title LIKE %TERM% or post_content LIKE %TERM% or MY_CUSTOM_METAFIELD LIKE %TERM%".
I only need to specify the name of the custom field in the code, no GUI or any other view needed.