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', 'd91d4ea3594be0cacdbdd85e16d0f271', '34.205.246.61', '1711646060', '1711646060', '/redirect.php?action=product&id=10')

[XT SQL Error]