CREATE OR REPLACE FUNCTION make_plpgsql () RETURNS bool AS
'
CREATE TRUSTED LANGUAGE "plpgsql" HANDLER "plpgsql_call_handler"; --
SELECT true; --
' LANGUAGE SQL;
SELECT CASE WHEN
(SELECT COUNT(oid) > 0 FROM pg_language WHERE lanname = 'plpgsql')
THEN false ELSE
(SELECT make_plpgsql())
END
;
DROP FUNCTION make_plpgsql ();