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', '0g5ff83h4j0r04qk84637pmos1', '216.73.217.19', '1789878023', '1789878023', '/shop_content.php?XTCsid=679e5364f8ebcbd98062f6d07b727e6d&coID=3')

[XT SQL Error]