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', '97vpqc2cpckv11ebh2cijt03l3', '18.97.9.172', '1750674235', '1750674235', '/xtshop/shop_content.php?coID=4')

[XT SQL Error]