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', '2kjl06ia4fuqcl8cj2r8767eh7', '216.73.216.59', '1786919928', '1786919928', '/index.php?XTCsid=7f3d063595fd0cf7dd24ecea4b1409d6&cat=c5_Crockery.html')

[XT SQL Error]