Bolt\Storage\Query\SearchQuery::getWhereExpression PHP Method

    public function getWhereExpression()
    {
        if (!count($this->filters)) {
            return null;
        }
        $expr = $this->qb->expr()->orX();
        /** @var Filter $filter */
        foreach ($this->filters as $filter) {
            $expr = $expr->add($filter->getExpression());
        }
        return $expr;
    }