How do I query using fields inside the new PostgreSQL JSON datatype?

Question

I am looking for some docs and/or examples for the new JSON functions in PostgreSQL 9.2.

Specifically, given a series of JSON records:

[
  {name: \"         


        

Answer 1

With postgres 9.3 use -> for object access. 4 example

seed.rb

se = SmartElement.new
se.data = 
{
    params:
    [
        {
            type: 1,
            code: 1,
            value: 2012,
            description: 'year of producction'
        },
        {
            type: 1,
            code: 2,
            value: 30,
            description: 'length'
        }
    ]
}

se.save

rails c

SELECT data->'params'->0 as data FROM smart_elements;

returns

                                 data
----------------------------------------------------------------------
 {"type":1,"code":1,"value":2012,"description":"year of producction"}
(1 row)

You can continue nesting

SELECT data->'params'->0->'type' as data FROM smart_elements;

return

 data
------
 1
(1 row)