postgres_json_queries.sql

-- find rows where a certain key exists
select
  *
from
  my_table
where
  json_field::jsonb ? 'key_i_want'
;

-- get certain key from json field
select
  json_field::jsonb -> 'key_i_want'
from
  my_table
;

-- the following syntax also works for referencing particular fields
select
  json_field ->> 'key_i_want'
from
  my_table
where
  json_field::jsonb ? 'some_qualifier' and
  json_field ->> 'other_key' = 'blah'
;