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', 'd44de5472ef01f2edd30734a0f3991eb', '34.229.24.100', '1563486105', '1563486105', '/index.php/cat/c140_Basic-100--Baumwolle.html')

[XT SQL Error]