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', '1ioicrvgll0aqj7b4r1pkrdgh3', '3.92.28.84', '1563568068', '1563568068', '/product_info.php/info/p44_DTD-Bojentasche.html')

[XT SQL Error]