src/Finder.php
public function ids()
    {
        $ids = $this->connection->executeFirstColumn($this->getSelectIdsSql());

        return empty($ids) ? [] : $ids;
    }
public function ids()
    {
        $ids = $this->connection->executeFirstColumn($this->getSelectIdsSql());

        return empty($ids) ? [] : $ids;
    }
Return array of ID-s that match the given criteria.

@return int[]