Displaying WordPress authors sorted by recent activity

A few weeks ago I ran into someone on the WordPress StackExchange wanting to sort his list of authors by recent activity – the author with the most recently published article first, etc. This type of sorting isn’t currently possible using the get_users() function(codex), nor the WP_User_Query class (codex), but it can be done – here’s how:

Let’s assume you currently have something similar to the below in your author.php (or archive.php) theme file:

$users = get_users();
foreach ( $users as $user ) {
     // HTML for each author using the $user object
}

You can make use of the $wpdb global object (codex) to make a direct SQL query that returns a list of author IDs sorted by recent activity:

global $wpdb;
$user_ids = $wpdb->get_results(
    "
    SELECT DISTINCT post_author
    FROM $wpdb->posts
    ORDER BY post_date DESC 
    "
);

You can then loop through this list of author IDs, retrieve the $user object with the get_user_by() function (codex), and write out your HTML save as before:

if ( $user_ids ) {
    foreach ( $user_ids as $user_id ) {
    $user = get_user_by( 'id', $user_id );
         // HTML for each author using the $user object
    }
}