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', 'o3qciv39bcorfs7gcp6m3t3e90', '18.232.99.123', '1563494060', '1563494060', '/')

[XT SQL Error]