public function walkOrderByItem($orderByItem)
{
$sql = parent::walkOrderByItem($orderByItem);
$hint = $this->getQuery()->getHint('sortableNulls.fields');
$expr = $orderByItem->expression;
$type = strtoupper($orderByItem->type);
if (is_array($hint) && count($hint)) {
// check for a state field
if ($expr instanceof Query\AST\PathExpression && $expr->type == Query\AST\PathExpression::TYPE_STATE_FIELD) {
$fieldName = $expr->field;
$dqlAlias = $expr->identificationVariable . (!empty($parts) ? '.' . implode('.', $parts) : '');
$search = $this->walkPathExpression($expr) . ' ' . $type;
$index = $dqlAlias . '.' . $fieldName;
$sql = str_replace($search, $search . ' ' . $hint[$index], $sql);
}
}
return $sql;
}