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', 't102hi1hv8h67pc8k0b2v1j9j7', '216.73.216.82', '1752526127', '1752526127', '/product_info.php?info=p2_Bavarian-Pennant-Chain.html&XTCsid=c5d9d9a5780af7d5707e3b2046ece3fe')

[XT SQL Error]