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', '3fjsbof1sqmbdi2v2cq0m79uj5', '18.97.9.168', '1742461816', '1742461816', '/xtshop/product_info.php?info=p600_.html')

[XT SQL Error]