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', '78b5p53o1uuhia5oa5ifkle6t2', '216.73.216.9', '1758185697', '1758185697', '/shop_content.php?XTCsid=1ce6d0a6925740e42ccf6986944a240a&coID=7')

[XT SQL Error]