Insert values if records don't already exist in Postgres

Question

I'd like to get this working, but Postgres doesn't like having the WHERE clause in this type of insert.

  INSERT INTO keys(name, value) VALUES
    ('blah', 'true')
  WHERE NOT EXISTS (
    SELECT 1 FROM keys WHERE name='blah'
  );

Answer 1

In Postgres, there is a really nice way to do that:

INSERT INTO keys(name, value) 
    SELECT 'blah', 'true'
WHERE NOT EXISTS (
    SELECT 1 FROM keys WHERE name='blah'
);

hope that helps.-

Answer 2

In Postgresql 9.5 you can now use on conflict do nothing

insert into KEYS (name, value) values (
'blah', 'true') on conflict (name) do nothing;