An example of how to use PDO and a simple repository and POPO entity might work, in contrast with a large ORM

CountyElectionResult.php

<?php
namespace MyApp\Domain;

class CountyElectionResult
{
    /**
     * @var string
     */
    private $county;

    /**
     * @var string
     */
    private $office;

    /**
     * @var array[]
     */
    private $candidateData = [];

    public function __construct($county, $office, array $candidateData)
    {
        $this->county = $county;
        $this->office = $office;
        foreach($candidateData as $singleCandidate) {
            $this->addCandidateData($singleCandidate);
        }
    }

    private function addCandidateData(array $singleCandidate)
    {
        $this->candidateData[] = [
            'id'    => $singleCandidate['id'],
            'name'  => $singleCandidate['name'],
            'party' => $singleCandidate['party'],
            'total' => $singleCandidate['total'],
        ];
    }

    public function getCounty()
    {
        return $this->county;
    }

    public function getOffice()
    {
        return $this->office;
    }

    /**
     * @return int
     */
    public function getTotal()
    {
        return array_sum( array_column($this->candidateData, 'total') );
    }

    public function getCandidateData()
    {
        return $this->candidateData;
    }

    /**
     * Election result candidate data in a nested associative array, with party as the key
     * and a nested array of candidate data as the value
     *
     * @return array[]
     */
    public function getCandidateDataByParty()
    {
        $dataByParty = [];
        foreach($this->candidateData as $singleCandidate) {
            $party = $singleCandidate['party'];
            $dataByParty[$party][] = $singleCandidate;
        }
        return $dataByParty;
    }

    public function toArray()
    {
        return [
            'county'            => $this->county,
            'office'            => $this->office,
            'candidate_data'    => $this->candidateData
        ];
    }
}

PdoRepositorySample.php

<?php
namespace MyApp\Infrastructure;

use MyApp\Domain\RepositorySample;
use MyApp\Domain\CountyElectionResult
use PDO;

class PdoRepositorySample implements RepositorySample
{
    /**
     * @var PDO
     */
    private $pdo;
    
    /** constructor omitted for brevity */
    
    /**
     * @param string $sql
     * @param array|mixed $bindings
     * @param int $fetchMode
     * @return array
     */
    protected function queryAndFetch($sql, $bindings = [], $fetchMode = PDO::FETCH_ASSOC)
    {
        $bindings = (array) $bindings;
        
        $statement = $this->pdo->prepare($sql);
        $statement->execute($bindings);
        $results = $statement->fetchAll($fetchMode);
        
        //Ensure a reference to the PDO statement doesn't hold open the database connection
        $statement->closeCursor();
        $statement = null;

        return $results;
    }
    
    /**
     * @param string $county
     * @return CountyElectionResult[]
     */   
    public function getResultsForCounty($county)
    {
        $sql = 'SELECT BallotOfficeName, Total, BallotName, Party FROM SampleTable';
        $sql .= ' WHERE County = ? GROUP BY BallotOfficeName, BallotName';
        $sql .= ' ORDER BY BallotOrder, District, DistXRef, CandOrder';

        $results = $this->queryAndFetch($sql, $county, PDO::FETCH_GROUP);
        $mappedResults = [];
        foreach($results as $office => $resultsForOffice) {
            $mappedResults[] = $this->mapToElectionResult($office, $county, $resultsForOffice);
        }
        return $mappedResults;
    }

    /**
     * @param string $office
     * @param string $county
     * @param array[] $candidateData
     * @return CountyElectionResult
     */
    protected function mapToElectionResult($office, $county, array $candidateData)
    {
        //The CountyElectionResult
        $mappedCandidateData = array_map( function(array $singleCandidate) {
            return [
                'id'    => $singleCandidate['ID'],
                'name'  => $singleCandidate['BallotName'],
                'party' => $singleCandidate['Party'],
                'total' => $singleCandidate['Total'],
            ];
        }, $candidateData);

        return new CountyElectionResult($county, $office, $mappedCandidateData);
    }
}