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', 'nbm52o08o2ib3k81v2n0vo7ot7', '216.73.216.127', '1752881971', '1752881971', '/popup_content.php?coID=1&XTCsid=ee199fdb171da456469b100b0e4b3f11')

[XT SQL Error]