1366 - Incorrect integer value: '' for column `abtecsho_shop`.`whos_online`.`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', 'pgl8q8e4ngst0a6blnc93i55c4', '216.73.216.6', '1752388712', '1752388712', '/shop_content.php?coID=23')

[XT SQL Error]