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', '7t6cr9p859vqesu41ueb64d7a3', '216.73.216.222', '1765991321', '1765991321', '/index.php?XTCsid=d3095b02705efe527622b406f0082775')

[XT SQL Error]