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', '2v1l8dop3j32d6u1j9pn2eg0m6', '216.73.216.180', '1767360269', '1767360269', '/products_new.php?XTCsid=38f09672db884903e3803adf9d076819')

[XT SQL Error]