02-05 ALTER TABLE

01

We can add columns after creating the table, add a column for gpa with a type DECIMAL value, 3 digits before the decimal and 2 after the decimal 

CREATE TABLE student(
    student_id INT,
    name VARCHAR(20),
    major VARCHAR(20),
    PRIMARY KEY(student_id)
);
DESCRIBE student;
ALTER TABLE student ADD gpa DECIMAL(3,2);
ALTER TABLE student ADD gpa DECIMAL(3,2);

02

To remove a column use 

ALTER TABLE student DROP COLUMN gpa;