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', '1d98cde73df220f3b206c0515c6be92b', '216.73.216.42', '1763354952', '1763354952', '/shop/newsletter.php')

[XT SQL Error]