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', '7qdtgk9ojacunhupvob3slfqq5', '216.73.216.244', '1752214856', '1752214856', '/shop_content.php?coID=7&XTCsid=3f98699a7205aa16d7f8014dc7c0d34a')

[XT SQL Error]