Q:

insert into table with no value

I have a table which only has two column:
+------------------+-------------+----------------------------+
|  user_id         |  INT        |  AUTO_INCREMENT            |
+------------------+-------------+----------------------------+
|  user_timestamp  |  TIMESTAMP  | DEFAULT CURRENT_TIMESTAMP  |
+------------------+-------------+----------------------------+

Now I am quite confused how will I build my INSERT since all the values has default. I have this but seems not working $query = "INSERT INTO tt_users (user_id) VALUES ()";. I just want MySQL to insert a new user_id which I will retrieve using lastInsertID. Pardon, this is my first time doing this.

A:

INSERT INTO tt_users (user_id) VALUES (null)

