create table WAnswer
(
  RequestId INTEGER,
  groupId INTEGER,
  error INTEGER,
  errorString varchar(255)
);
CREATE OR REPLACE FUNCTION selAnswer(integer) RETURNS RECORD AS $$
DECLARE
   id  ALIAS FOR $1;
   rec RECORD;
BEGIN
   SELECT * INTO rec from WAnswer WHERE RequestId = id;
   RETURN rec;
END;
$$ LANGUAGE plpgsql;

QSqlQuery answQuery(db);
answQuery.prepare("SELECT selAnswer(:requestId)");
answQuery.bindValue(":requestId", requestId);
answQuery.exec();

if(answQuery.next()){
    int groupId = answQuery.value(1).toInt();
    ...
}

CREATE OR REPLACE FUNCTION selGroupFunctions(integer) 
RETURNS TABLE(RequestId_ INTEGER, funId_ INTEGER, enabled_ boolean) AS $$
DECLARE
   id  ALIAS FOR $1;
BEGIN
   RETURN QUERY SELECT RequestId, funId, enabled from WGroupFunctions WHERE RequestId = id; 
END;
$$ LANGUAGE plpgsql;

CREATE FUNCTION selAnswer(integer) RETURNS SETOF WAnswer AS $$
BEGIN
   RETURN QUERY SELECT * from WAnswer WHERE RequestId = $1;
END;
$$ LANGUAGE plpgsql;

        QSqlQuery answQuery(db);
        answQuery.prepare("SELECT * from selAnswer(:requestId) ");
        answQuery.bindValue(":requestId", requestId);
        answQuery.exec();
        QSqlRecord answRec = answQuery.record();

        if(answQuery.next()){
            groupVars.groupId = answQuery.value(answRec.indexOf("groupId")).toInt();
            groupVars.error = answQuery.value(answRec.indexOf("error")).toInt();
            groupVars.errorString = answQuery.value(answRec.indexOf("errorString")).toString();
            ...
        }