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', 'd147kmm0c021j5lualfnkv6el1', '216.73.217.95', '1792829854', '1792829854', '/product_info.php?XTCsid=0308d34f52db367f9a7068f51bec2a23&info=p2_Bavarian-Pennant-Chain.html')

[XT SQL Error]