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', '55gpcgcepnultpoa8p6j31hll3', '18.189.13.48', '1746872825', '1746872825', '/xtshop/account_password.php')

[XT SQL Error]