TYPO3 Core

// support both sorting fields to sort child object sorting in FE

// if both fields are there, foreign_sortby has the higher priority

if (isset($columnConfiguration['foreign_sortby'])) {

$columnMap->setChildSortByFieldName($columnConfiguration['foreign_sortby']);

} elseif ($columnConfiguration['type'] === 'inline' && isset($columnConfiguration['foreign_default_sortby'])) {

// explode foreign_default_sortby because it is used as the "ORDER BY" statement

// http://docs.typo3.org/typo3cms/TCAReference/Reference/Columns/Inline/Index.html

$orderingPairs = \TYPO3\CMS\Core\Utility\GeneralUtility::trimExplode(',', $columnConfiguration['foreign_default_sortby']);

foreach ($orderingPairs as $orderingPair) {

list($field, $order) = \TYPO3\CMS\Core\Utility\GeneralUtility::trimExplode(' ', $orderingPair);

if (strtoupper($order) === 'DESC') {

$fieldNamesAndOrders[$field] = \TYPO3\CMS\Extbase\Persistence\QueryInterface::ORDER_DESCENDING;

} else {

$fieldNamesAndOrders[$field] = \TYPO3\CMS\Extbase\Persistence\QueryInterface::ORDER_ASCENDING;

}

}

$columnMap->setChildSortByFieldNamesAndOrders($fieldNamesAndOrders);

}