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', '6evbv18uu8qanu0tv3t4nvkpu7', '216.73.216.170', '1761986929', '1761986929', '/product_info.php?XTCsid=ee199fdb171da456469b100b0e4b3f11&info=p18_Fun-Hat.html')

[XT SQL Error]