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', '6m15o0ojbku3h6v4ok4g7vl2i1', '216.73.216.110', '1752059164', '1752059164', '/product_info.php?info=p6_100-Paper-Plates.html&XTCsid=15cbbc13723f7bc63afaf1294f637517')

[XT SQL Error]