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', 'hdni7ujndip321o170j0do29i4', '216.73.216.7', '1758246094', '1758246094', '/product_info.php?XTCsid=cdfc0f2ea8be6cebe1f6056b0a37d83f&info=p17_20-Tissue-Napkins.html')

[XT SQL Error]