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', '7sjdk6l3b288hjhc8von81rn51', '216.73.216.7', '1758227590', '1758227590', '/index.php?XTCsid=adc8c520bddaa9e02a40df1e2a90f128&cat=c12_Music.html')

[XT SQL Error]