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', 'ufjd1nt909oo60bu37e58ut5n2', '18.234.88.196', '1558465311', '1558465311', '/lkw_plane_tasche_lkw_plane/index.php/cat/c2_konfigurator_taschen_geldboerse_brieftasche_schluesselanhaenger_aus_lkw_plane.html')

[XT SQL Error]