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', '735kmgbe84nhefv8p280v0urp0', '52.23.234.7', '1558846956', '1558846956', '/')

[XT SQL Error]