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', '5offbkdb3vkuld68g8l59g0mr0', '2600:1f28:365:80b0:411a:328d:9c62:c3fb', '1773376492', '1773376492', '/')

[XT SQL Error]