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', 'adqerlb33ihipk03igmnbm37e2', '216.73.216.244', '1752214163', '1752214163', '/shop_content.php?coID=3&XTCsid=d3f81aac1b90a5822d8663a3af39931e')

[XT SQL Error]