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', 'ralnp6ep7os912vsvi3uq1e836', '216.73.216.113', '1752221649', '1752221649', '/xtshop/product_info.php?info=p1017_.html')

[XT SQL Error]