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', 'd9fa0aa1d1de91225507f0b95dbe64fb', '34.229.24.100', '1563484497', '1563484497', '/index.php')

[XT SQL Error]