public function addOr($p1, $p2 = null, $p3 = null, $preferColumnCondition = true)
    {
        $rightCriterion = $this->getCriterionForCondition($p1, $p2, $p3);

        $leftCriterion = $this->getLastCriterion();

        if (null !== $leftCriterion) {
            // combine the given criterion with the existing one with an 'OR'
            $leftCriterion->addOr($rightCriterion);
        } else {
            // nothing to do OR / AND with, so make it first condition
            $this->add($rightCriterion);
        }

        return $this;
    }