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', 't95pn86umg09qi2m3eta3gkb51', '54.80.39.89', '1496106921', '1496106921', '/')

[XT SQL Error]