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', 'v36p0u7gnokcjknf5n8m1ir1u7', '216.73.216.141', '1751426283', '1751426283', '/product_info.php?info=p14_65-drinking-cups-1-2-Liter.html&XTCsid=2f0d32e80e0e3a7e9efdd2dc2a571c8d')

[XT SQL Error]