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', 'taek49fgoro7nctvu6pqhsnpv2', '107.22.127.78', '1493220781', '1493220781', '/product_info.php?info=p132_Da-war-mal-was---.html&XTCsid=h84gj4ie5gil7kbps97mfctho1')

[XT SQL Error]