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', 'n2inh4kvuup06m7rj92bhphh45', '3.85.92.139', '1561472056', '1561472056', '/index.php/cat/c3_Masken.html')

[XT SQL Error]