public function applyOrderBy(SelectQuery $query)
    {
        foreach ($this->sortColumns as $column => $direction) {
            $query->orderBy(
                $column,
                $direction === Query::SORT_ASC ? SelectQuery::ASC : SelectQuery::DESC
            );
        }
        // @todo Review needed
        // The following line was added because without it, loading sub user groups through the Public API
        // fails with the database error "Unknown column sort_column_0". The change does not break any
        // integration tests or legacy persistence tests, but it can break something else, so review is needed
        // Discussion: https://github.com/ezsystems/ezpublish-kernel/commit/8749d0977307858c3e2a7d82f3be90fa21973357#L1R102
        $this->sortColumns = array();
    }