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', 'g6gd63d5389n9ppsd42pk7mh54', '216.73.216.185', '1752883101', '1752883101', '/product_info.php?info=p21_Paper-tablecloth-10-meters.html&XTCsid=81fba26e1f006e30d12d9ee4d58a4030')

[XT SQL Error]