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', '39d07bf0d4820ff7b57245180b66e19f', '34.229.24.100', '1563487734', '1563487734', '/shop_content.php/coID/0/product/Kreditkarten')

[XT SQL Error]