Postgresql: JSON operations cheatcheet

json.sql

-- Select empty JSON field
select * from mytable where jsonfield::text = '{}'

-- Select 'title' within JSON field
select * from mytable where jsonfield->>'title' = 'Great Expectations'
select * from mytable where jsonfield->>'title' like 'Great Expectations%'

-- Update: Postgres 9.3 you must update whole field
update mytable set jsonfield = '{}' where id = 1