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', 'c3e9abdc3e1cb21fdbba9c2ffcdff705', '54.159.116.24', '1711695496', '1711695496', '/product_info.php/info/p30_Heidehonig.html')

[XT SQL Error]