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', '3h94lo6kbhh03s0qn9b8dnngf2', '216.73.216.197', '1751515050', '1751515050', '/index.php?cat=c6_Foodstuffs.html&XTCsid=3e3fcef0642c69bbf707de3c0bc1cf9c')

[XT SQL Error]