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', '4806f6b997d875t7i3psvp6k73', '216.73.216.147', '1751585433', '1751585433', '/product_info.php?info=p11_Fan-for-decorations.html&XTCsid=81fba26e1f006e30d12d9ee4d58a4030')

[XT SQL Error]