CREATE TABLE student (
  id int primary key,
  name varchar(50),
  age int
);

INSERT INTO student VALUES (1, "Alex", 18);

INSERT INTO student VALUES (2, "Maria", 19), (4,"Zack",19);
INSERT INTO student (id,age) VALUES(5,20);
ALTER TABLE  student
ADD COLUMN last_name varchar(50);
ALTER TABLE student
CHANGE COLUMN name first_name varchar(50);
SELECT *FROM student;
ALTER TABLE student 
ADD CONSTRAINT c1 CHECK (age >= 18);

SHOW COLUMNS FROM student;

ALTER TABLE student
DROP CONSTRAINT c1;

CREATE TABLE majors (
    dept_id int PRIMARY KEY,
    dept varchar(50),
    major varchar(50),
    student_id int,
    FOREIGN KEY(student_id)REFERENCES student(id)
);