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', 'o39me35dni50ep08mel5orlad0', '216.73.216.118', '1761599636', '1761599636', '/product_info.php?XTCsid=81fba26e1f006e30d12d9ee4d58a4030&info=p12_33-feet-crape-paper.html')

[XT SQL Error]