Insert data from CONCAT data from one table using select statement into new table

[Tim burke]

This it what I have so far but I think I'm doing something wrong.

INSERT INTO username (username)
SELECT (concat(substring(LastName,1,2),substring(IDNumber,1,4))) FROM person
WHERE person.IDNumber = username.IDNumber;

username is the new table and the column name is also username. I'm trying to automatically create usernames from the first 2 digits of the users last name and the first 4 digits of their ID Number. The users last name and ID number are located in a table called "person".

This is the statement I used to create the new table called username.

CREATE TABLE username (
usernameID INT AUTO_INCREMENT PRIMARY KEY,
IDNumber INT NOT NULL,
username CHAR(6) NOT NULL,
FOREIGN KEY (IDNumber) REFERENCES person(IDNumber));

This table is empty at the moment but I want it to populate using the data from the persons table automatically. Hopefully someone can direct me how to do this.

Thanks