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', 'od8gg5glap4t5a0cmv348cffj1', '216.73.216.113', '1752884175', '1752884175', '/product_info.php?info=p15_25-balloons.html&XTCsid=c407ede434192d8d024c7c2f06b2be8c')

[XT SQL Error]