I've been playing around with JSON(B) columns in Postgres 9.4. I haven't found a great way to join from one value into another (without crazy JSON reconstruction), but this is close.

jsonb_columns

fritzy=# select * from authors;
 id |          value
----+--------------------------
  1 | {"name": "Nathan Fritz"}
(1 row)

fritzy=# select * from books;
 id |                       value
----+----------------------------------------------------
  1 | {"title": "Ham, and Eating It", "author": 1}
  2 | {"title": "Learn How To Read Gooder", "author": 1}
(2 rows)

fritzy=# select value author, (select json_agg(value) from books where authors.id=(value->'author')::text::int) books from authors;
          author          |                                               books
--------------------------+----------------------------------------------------------------------------------------------------
 {"name": "Nathan Fritz"} | [{"title": "Ham, and Eating It", "author": 1}, {"title": "Learn How To Read Gooder", "author": 1}]
(1 row)

fritzy=# select json_build_object('author', value, 'books', (select json_agg(value) from books where authors.id::text=(value->'author')::text)) books from authors;
                                                                        books
-----------------------------------------------------------------------------------------------------------------------------------------------------
 {"author" : {"name": "Nathan Fritz"}, "books" : [{"title": "Ham, and Eating It", "author": 1}, {"title": "Learn How To Read Gooder", "author": 1}]}
(1 row)