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', 'kfjlp62koaglcn1fnhks4rplr7', '216.73.216.141', '1751422398', '1751422398', '/index.php?XTCsid=d3aeae78ea7b7e9600a4cc5c86a9a047')

[XT SQL Error]