Customize the footer section

functions.php

<?php
// Do NOT include the PHP opening tag

// Customize the footer section
add_filter('genesis_footer_creds_text', 'bdfg_footer_creds_text');
function bdfg_footer_creds_text($creds) {
  global $wpdb;
  $table = $wpdb->prefix . 'posts';
  $lastDate = date('Y');
  $firstDate = $wpdb->get_var("SELECT YEAR(post_date) FROM $table ORDER BY post_date LIMIT 1");
 
  $text = __(' &middot; <a href="https://rainastudio.com/">RainaStudio.com</a> &middot; Built on <a href="http://wordpress.org">WordPress</a>', 'genesis');
  if($lastDate == $firstDate) $creds = "Copyright ©$firstDate-$lastDate " .$text;
  else $creds = "Copyright ©$firstDate-$lastDate" .$text;
  return $creds;
}