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', 't4cda77o984tht2hl5q4ciaii6', '216.73.216.110', '1752049916', '1752049916', '/product_info.php?info=p6_100-Paper-Plates.html&XTCsid=15cbbc13723f7bc63afaf1294f637517')

[XT SQL Error]