在jsp中，用mysql查询报版本错误

这是我报错的代码：
            String strId = request.getParameter("id");
  if(strId == null || strId.trim().equals("")){
      out.println("Error ID");
      return;
  }

 
      int id = Integer.parseInt(strId);
  System.out.println("Id" +  id  );
 
 
  Connection conn = DB.getConn();
  String sql = "select * from article where rootid = " + strId + "order by pdate asc";    //报错的主题行
  Statement stmt = DB.createStmt(conn);
  ResultSet rs = DB.executeQuery(stmt,sql);
  List <Article>  articles= new ArrayList <Article>();

  while(rs.next()){
      Article a = new Article();
      a.initfromRs(rs);
      articles.add(a);
  }


报错的错是：    You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'by pdate asc' at line 1
               

  我再网上查了一下，没有看到一个合适我这问题的答案，有的好像说是什么mysql版本问题。以前也遇到过类似的问题