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', 'smekepaglvtn8f2pqmi7ij0ld2', '216.73.216.185', '1752882871', '1752882871', '/index.php?XTCsid=880b267136b28fa870157304bf093b31')

[XT SQL Error]