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', '3euo9uvim1nih0f4vfvdeirtu2', '216.73.216.99', '1761929362', '1761929362', '/shop_content.php?XTCsid=0832187515ca706758d8e1ce01e34faf&coID=4')

[XT SQL Error]