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', '9qf5ljtpbi1apvrdlaqepamup5', '216.73.216.147', '1751832937', '1751832937', '/product_info.php?info=p5_Large-Garland-33-feet.html&XTCsid=0308d34f52db367f9a7068f51bec2a23')

[XT SQL Error]