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', '7mk1ikp97qgb5543570p2usmd6', '18.218.108.184', '1746767694', '1746767694', '/xtshop/index.php?cat=c74_.html')

[XT SQL Error]