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', 'quh9v1pbvit6vljqsrq1f2uoq5', '216.73.216.185', '1752524596', '1752524596', '/product_info.php?info=p18_Fun-Hat.html&XTCsid=ec23ca965190a8290c666be9c9947acd')

[XT SQL Error]