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', 'h8c0srq3qu0nt1gjbdq7dnl2e4', '216.73.216.174', '1761981355', '1761981355', '/xtshop/index.php?cat=c106_.html')

[XT SQL Error]