text: DROP TABLE IF EXISTS user;
  
  CREATE TABLE user
  (
      id   int PRIMARY KEY auto_increment,
      name VARCHAR(100),
      age  int,
      type int comment '1:学生, 2:工人, 3:无业'
  );
  
  INSERT INTO user(name, age, type)
  VALUES ('alice', 16, 1);
  
  INSERT INTO user(name, age, type)
  VALUES ('bob', 17, 1);
  
  INSERT INTO user(name, age, type)
  VALUES ('tom', 17, 2);
  
  INSERT INTO user(name, age, type)
  VALUES ('dev', 16, 1);
  
  INSERT INTO user(name, age, type)
  VALUES ('test', 19, 3);
  
  INSERT INTO user(name, age, type)
  VALUES ('ba', 16, 3);