mysql_num_rows issue

  first_row = 1;  curs.execute("SELECT id, port_id, category, port FROM cache_clearing_ports ORDER BY id")  for row in curs.dictfetchall():    if (first_row):      min_id = row['id']      max_id = row['id']      first_row = 0    min_id = min(row['id']);    max_id = max(row['id']);    # other processing goes here