1062 - Duplicate entry '0' for key 'PRIMARY'

insert into whos_online (customer_id, full_name, session_id, ip_address, time_entry, time_last_click, last_page_url) values ('0', 'Guest', '', '3.235.120.150', '1627406025', '1627406025', '/product_info.php/info/p336_---------------------------.html')

[XT SQL Error]