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', '7f4ab89c88bfd39038ee9431b96ad5c5', '3.14.83.223', '1714117713', '1714117713', '/product_info.php/info/p50_Bluetenpollen--200-Gramm-.html')

[XT SQL Error]