Help me in solving GSQ08 problem i am a beginner

help
,
1

My issue

unable to solve

My code

/* Write a query to add a column 'Designation' to the table and set 'Null' as the default value. Output the entire table.*/

INSERT INTO employee(Employee_id,Employee_Name,Department)
VALUES(1,'Kayla Thompson ', 'Sales');
INSERT INTO employee(Employee_id,Employee_Name,Department)
VALUES(2,'Ethan Chen', 'Operations');
INSERT INTO employee(Employee_id,Employee_Name,Department)
VALUES(3,'Julia Lee', 'Hr');


ALTER TABLE employee
ADD COLUMN  Designation TEXT default NULL;

Learning course: Learn SQL
Problem Link: CodeChef: Practical coding for everyone