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', '6aes0v6b1fvpg45e2ptnimbg13', '3.148.232.123', '1746764923', '1746764923', '/xtshop/index.php?cat=c75_.html')

[XT SQL Error]