-- create a table
CREATE TABLE students (
  stu_id INTEGER PRIMARY KEY,
  name TEXT NOT NULL,
  gender TEXT NOT NULL,
  grade INTEGER,
  course_id INTEGER
);

CREATE TABLE courses (
    course_id INTEGER PRIMARY KEY,
    course_name TEXT,
    instructor TEXT
);
-- insert some values
INSERT INTO students VALUES 
    (1, 'Ryan', 'M', 6, 2),
    (2, 'Joanna', 'F', 7, 2),
    (3, 'Joanna', 'F', 8, 2),
    (4, 'Joanna', 'F', 9, 2)
    ;

-- fetch some values
#SELECT COUNT(*) FROM students WHERE name="Joanna";
UPDATE students SET name='bb' WHERE stu_id IN (3, 4);
SELECT * FROM students;

DELETE FROM students WHERE stu_id=3 OR stu_id=4;
SELECT * FROM students;