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', '3k7m5e6lp437715ro908a2sik7', '18.224.137.108', '1746767279', '1746767279', '/xtshop/index.php?cat=c50_.html')

[XT SQL Error]