1366 - Incorrect integer value: '' for column 'customer_id' at row 1

insert into whos_online (customer_id, full_name, session_id, ip_address, time_entry, time_last_click, last_page_url) values ('', 'Guest', '5h1fjcc7jf6s7ftl3hqluri285', '216.73.216.70', '1752612767', '1752612767', '/shop_content.php?coID=2&XTCsid=98fab66f7c5bcfa7f4c82f0bdb1cf869')

[XT SQL Error]