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', 'ro429t19fqg62mrr7s5e55cld7', '18.221.87.167', '1746788231', '1746788231', '/xtshop/index.php')

[XT SQL Error]