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', '23pdo4rmc1ll3n42fcf9pjlod1', '216.73.216.28', '1775687085', '1775687085', '/product_info.php?XTCsid=75dc59d6a30660e0992222d2318ca53e&info=p17_20-Tissue-Napkins.html')

[XT SQL Error]