text: USE db_escola_softblue;
  
  ALTER TABLE tb_students
  ADD COLUMN bithday VARCHAR(10);
  
  ALTER TABLE tb_students
  CHANGE bithday birthday VARCHAR(10);
  
  ALTER TABLE tb_students
  MODIFY birthday DATE;
  
  CREATE INDEX index_name_student
  ON tb_students(name);
  
  ALTER TABLE tb_instructors
  ADD COLUMN email VARCHAR(100);
  
  CREATE INDEX index_course_instructor
  ON tb_courses(id_crs_inst);
  
  ALTER TABLE tb_instructors
  DROP COLUMN email;
  
  SELECT * FROM tb_students;
  
  SELECT * FROM tb_instructors;
  
  SELECT * FROM tb_courses;
  