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', '4egl8lpjq4n10ad55vosh7bek5', '216.73.216.113', '1752884241', '1752884241', '/shop_content.php?coID=7&XTCsid=38f09672db884903e3803adf9d076819')

[XT SQL Error]