Get the Products in the order of the uid comma list in TYPO3 8 Source: https://www.derhansen.de/2017/05/mysql-field-function-in-typo3-87-with-doctrine.html

Get entity by order of the uid comma list

<?php

use TYPO3\CMS\Core\Database\ConnectionPool;
use TYPO3\CMS\Core\Database\Query\QueryBuilder;
use TYPO3\CMS\Core\Utility\GeneralUtility;
use TYPO3\CMS\Extbase\Persistence\Generic\Mapper\DataMapper;

/**
 * The repository for ExampleRepository
 */
class ExampleRepository extends \TYPO3\CMS\Extbase\Persistence\Repository {
  
  /**
     * Find all results by a list of uids and order by this uid list
     *
     * @param String $uidList List of uids
     * @return array
     */
	public function findAllByCommaIdString(String $uidList) {
        $uids = GeneralUtility::intExplode(',', $uidList, true);
        if ($uidList === '' || count($uids) === 0) {
            return [];
        }

        $dataMapper = GeneralUtility::makeInstance(DataMapper::class);

        /** @var QueryBuilder $queryBuilder */
        $queryBuilder = GeneralUtility::makeInstance(ConnectionPool::class)
            ->getQueryBuilderForTable('tx_example_domain_model_example');

        $rows = $queryBuilder
            ->select('*')
            ->from('tx_example_domain_model_example')
            ->where($queryBuilder->expr()->in('uid', $uids))
            ->add(
                'orderBy',
                'FIELD(tx_example_domain_model_example.uid,' . implode(',', $uids) . ')'
            )
            ->execute()
            ->fetchAll();

        return $dataMapper->map(\FooBar\Example\Domain\Model\Example::class, $rows);
    }
}