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', '7d5rn44mgjt0k7logc5nkb3bu6', '18.97.9.173', '1742636012', '1742636012', '/xtshop/index.php')

[XT SQL Error]