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', '36bf89bc3006bebfa55ca7994da21b39', '3.209.81.51', '1711711746', '1711711746', '/index.php')

[XT SQL Error]