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', 'e21bf97dfb48e219607b6f49e5a02eb8', '3.237.34.21', '1709263794', '1709263794', '/account.php')

[XT SQL Error]