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', 'h6damdtq7eu7q6u89qi8l9bsm1', '216.73.217.165', '1790846390', '1790846390', '/xtshop/product_info.php?info=p722_.html')

[XT SQL Error]