private function loadTermsData()
{
$select = $this->getConnection()->select();
$itemIds = array_keys($this->_items);
$select->from(['exp' => $this->getTable(ThesaurusInterface::EXPANSION_TABLE_NAME)], [])->joinLeft(['ref' => $this->getTable(ThesaurusInterface::REFERENCE_TABLE_NAME)], "exp.thesaurus_id = ref.thesaurus_id AND exp.term_id = ref.term_id", [])->where('exp.thesaurus_id IN (?)', $itemIds)->group(["exp.thesaurus_id", "exp.term_id"])->columns(['thesaurus_id' => 'exp.thesaurus_id', 'expansions_terms' => new \Zend_Db_Expr("GROUP_CONCAT(exp.term)"), 'expanded_term' => 'ref.term']);
$this->addTermData($this->getConnection()->fetchAll($select));
}