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', '3fq8k9s4h5iqga6487idv02v00', '216.73.217.60', '1780137677', '1780137677', '/shop_content.php?XTCsid=53b3ca17e11023a1f7ae6e1aa45a0ce7&coID=8')

[XT SQL Error]