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', 'kmn9mt0tr0p7ehip3et6r4s4c0', '3.145.45.170', '1746762254', '1746762254', '/xtshop/product_info.php?info=p735_.html')

[XT SQL Error]