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', '16kon7avn1s2v0g1o7psnude32', '3.85.92.139', '1561469851', '1561469851', '/product_info.php/info/p36_DTD---single-tank-adapter--STA-.html')

[XT SQL Error]