How can I change the admin search posts fields?

Question

I have a custom post type that includes many custom fields. I would like to add them as a search target to admin search.

Currently the admin search searches only the content and the title, I would like it to search these custom fields as well.

Is there a way to do that ?

Answer 1

It is possible, but you'll have to play a little bit with the actual query. As always, the furious posts_clauses filter comes to action:

function wpse_alter_posts_search( $pieces )
{
    global $wpdb;

    // Make the input save
    $search_string = like_escape( $_GET['s'] );

    // Your new WHERE clause
    $where  = $wpdb->prepare( 
         "
            $wpdb->postmeta.%s LIKE %s
         "
        ,'YOUR_COLUMN' // Should match your col name 1)
            ,"%{$search_string}%"
    );

    $pieces['where'] = str_replace( 'AND (((', "AND ((($where ", $pieces['where'] ); // Not sure if this exactly the same on your install 2)

    return $pieces;
}
add_filter( 'posts_clauses', 'wpse_alter_posts_search' );

---

NOTES

1. Could be that you need to unserialize some parts to be search able.
2. You better simply dump the $pieces to take a look into them, before altering the query (right after the $search_string was received).