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', 'ba1f42ae89e7fffeda888b538d8397e3', '216.73.217.165', '1780980990', '1780980990', '/shop/product_info.php?info=p10_.html')

[XT SQL Error]