CREATE OR REPLACE FUNCTION iff(cond BOOLEAN, value anyelement) RETURNS anyelement AS $$
BEGIN IF cond THEN RETURN value; ELSE RETURN NULL; END IF; END;
$$ LANGUAGE plpgsql;
CREATE OR REPLACE FUNCTION iff(cond BOOLEAN, value anyelement, else_value anyelement) RETURNS anyelement AS $$
BEGIN IF cond THEN RETURN value; ELSE RETURN else_value; END IF; END;
$$ LANGUAGE plpgsql;