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', '5eca5t3e9g5l43d17bo40e4221', '18.97.9.168', '1742456238', '1742456238', '/xtshop/shop_content.php?coID=1')

[XT SQL Error]