这里不需要自定义表-您可以使用用户元数据表和API.

然后创建一个WP Cron作业，每24小时运行一次（如果你有妄想症，可以更频繁地运行）。在回调中，使用以下内容查询在过去7天内注册的用户：

/*
 * Get all users registered after $start and before $end (dates in yyyy-mm-dd format)
 * Based on my answer to this question: http://wordpress.stackexchange.com/questions/51485/how-can-i-query-all-users-who-registered-today/51492#51492
 * @param (string) $start - start date in yyyy-mm-dd format
 * @param (string) $end - end date in yyyy-mm-dd format
 */
function wpse51485_get_users_registered($start=\'\', $end=\'\' ){
    global $wpdb;

    if( empty($start) )
        $date = date(\'Y-m-d\');

    if ( empty($end) )
        $end = $start;

    //Should probably validate input and throw up error. In any case, the following ensures the query is safe.

    $start_dt = new DateTime($start. \' 00:00:00\');
    $s = $start_dt->format(\'Y-m-d H:i:s\');

    $end_dt = new DateTime($end.\' 23:59:59\');
    $e = $end_dt->format(\'Y-m-d H:i:s\');

    $sql = $wpdb->prepare("SELECT wp_users.* FROM wp_users WHERE 1=1 AND CAST(user_registered AS DATE) BETWEEN %s AND %s ORDER BY user_login ASC",$s,$e);

    $users = $wpdb->get_results($sql);

    return $users;
 }