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', '166j42b545hqra09qm6nfesg21', '216.73.216.128', '1763231641', '1763231641', '/product_info.php?XTCsid=792dd2eece839333bab562194e3fb545&info=p10_3-packs-Blow-outs.html')

[XT SQL Error]