1366 - Incorrect integer value: '' for column `agentur`.`whos_online`.`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', '1ue0gs1258ksh3g7f4jg9pmf93', '23.21.4.239', '1600517037', '1600517037', '/')

[XT SQL Error]