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', 'etike0gpck00isdflil5h74pr5', '216.73.216.87', '1765563988', '1765563988', '/product_info.php?XTCsid=0832187515ca706758d8e1ce01e34faf&info=p15_25-balloons.html')

[XT SQL Error]