MYSQL null column not going to select

In this table , if I make following query

select * from table where order_id != 1

I think, I am supposed to get row no 18 & 19. But instead, the query can't not fetch any row.

I can rewrite the query like this

select * from table where (order_id != 1 or order_id is null)

https://stackoverflow.com/questions/37670677/mysql-select-query-can-not-fetch-data-with-null-value