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', 'nth4umk4tuno5td2co7p4le1g2', '216.73.216.52', '1792355050', '1792355050', '/xtshop/product_info.php?info=p962_.html')

[XT SQL Error]