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', 'ca8m0akg0qkrkc49fijp2q4pf7', '216.73.216.60', '1760455029', '1760455029', '/product_info.php?XTCsid=3547ee950f9337e348e5e07def1466f0&info=p17_20-Tissue-Napkins.html')

[XT SQL Error]