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', '49de29ceca409b7cc997632043fedbf3', '52.90.40.84', '1711667427', '1711667427', '/product_info.php/info/p29_Wildbluetenhonig.html')

[XT SQL Error]