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', '02b1602c4d9ddd5ebdd8e5abfcc0fd1a', '18.191.147.190', '1714183731', '1714183731', '/index.php')

[XT SQL Error]