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', 'oi4dksfdms5gu276vr3sf4hku7', '216.73.216.10', '1782747957', '1782747957', '/xtshop/product_info.php?info=p960_.html')

[XT SQL Error]