text: create table comment
  (
      no        int auto_increment
          primary key,
      couserid  varchar(100)                        null,
      postno    int                                 null,
      content   longtext                            null,
      coregtime timestamp default CURRENT_TIMESTAMP null,
      constraint post_no_comment
          foreign key (postno) references post (postno),
      constraint user_id_comment
          foreign key (couserid) references user (id)
  );
  
  create index post_no_comment_idx
      on comment (postno);
  
  create index user_id_comment_idx
      on comment (couserid);
  
  