Get Random Author if had post in last month

Hi, thanks in advance if anyone is able to help me with this. I am using the following code that gets a random author but only if they have at least 1 post. Is there anyway to modify this function so it only returns authors that have at least 1 post in the last month.

function get_random_author_wpa91320($role){
    global $wpdb;
    //this will get all users with posts
    $ids = $wpdb->get_col("
        SELECT DISTINCT post_author
        FROM $wpdb->posts, $wpdb->usermeta
        WHERE post_type = 'post'
        AND post_status = 'publish'
        AND user_id = <code>post_author</code>
        AND meta_key = 'wp_capabilities'
        AND meta_value LIKE '%\"{$role}\"%'
        "
    );
    return $ids[rand(0,count($ids) -1)];
}