postgresql - postgresql嵌套选择与地图

Question

我有以下结构：

CREATE TABLE folder (
  id integer primary key,
  name varchar(255)
);

CREATE TABLE folder_path (
  folder_id integer references folder(id),
  path ltree
);

INSERT INTO folder (id,name) VALUES (1,'f1');
INSERT INTO folder (id,name) VALUES (2,'f2');

INSERT INTO folder_path (folder_id, path) VALUES (1,'1');
INSERT INTO folder_path (folder_id, path) VALUES (2,'1.2');
INSERT INTO folder_path (folder_id, path) VALUES (2,'2');

并且需要选择所有文件夹及其路径，如下所示：

 [
   { id: 1,
     name: 'f1',
     paths: [
              [{id: 1, name: 'f1'}]
            ]
   }
   { id: 2, 
     name: 'f2',
     paths: [
              [{id: 1, name: 'f1'}, {id: 2, name: 'f2'}],
              [{id: 2, name: 'f2'}]
            ]
 ]

我怎样才能做到这一点？谢谢。sqlfiddle：http ://sqlfiddle.com/#!15/6b974/12