/**
   *  Function to validate a generated GUID / UUID
   *  @param string $guid GUID
   *  @return bool
   */
  function validGUID($guid){
    return preg_match('#^[a-z0-9]{8}-[a-z0-9]{4}-[a-z0-9]{4}-[a-z0-9]{4}-[a-z0-9]{12}$#', $guid);
  }

MySQL, PHP