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', '948dr6stl7hrhka4s4r28j26s6', '18.212.83.37', '1558247581', '1558247581', '/shop/index.php?XTCsid=948dr6stl7hrhka4s4r28j26s6')

[XT SQL Error]