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', 'ec31d1356aa8b4af7b905cab99572f8e', '34.229.24.100', '1563485936', '1563485936', '/index.php/cat/c358_brands.html')

[XT SQL Error]