How to run an ad-hoc script in PostgreSQL?

Question

I\'m trying to run this in PostgreSQL 9.2:

RAISE NOTICE \'hello, world!\';

And the server says:

Error : ERROR:  syntax erro         


        

Answer 1

Use an anonymous code block:

DO language plpgsql $$
BEGIN
  RAISE NOTICE 'hello, world!';
END
$$;

Variables are referenced using %:

RAISE NOTICE '%', variable_name;

Answer 2

simple example:

CREATE OR REPLACE FUNCTION test()     
RETURNS TRIGGER AS
'
DECLARE


num int;

 BEGIN
IF TG_OP = ''INSERT'' THEN
select count(*) into num from test_table;
IF num >= 1 THEN
RAISE WARNING ''Cannot Insert more than one row'';
RETURN OLD;
END IF;
ELSE
RETURN NEW;
END IF;

END;
' LANGUAGE plpgsql;

Answer 3

raise is PL/pgSQL only.

http://www.postgresql.org/docs/current/static/plpgsql-errors-and-messages.html

create or replace function r(error_message text) returns void as $$
begin
    raise notice '%', error_message;
end;
$$ language plpgsql;

select r('an error message');
NOTICE:  an error message