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', 'cu9mr3plq6lil6v54ftefd8g55', '216.73.216.10', '1762161345', '1762161345', '/index.php?XTCsid=adc8c520bddaa9e02a40df1e2a90f128&cat=c5_Crockery.html')

[XT SQL Error]