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', 'erk8g0paoljosnoq5seoo7k5q2', '3.14.134.62', '1746775569', '1746775569', '/xtshop/product_info.php?info=p600_.html')

[XT SQL Error]