public function getJoinSearchRule($tableJoin, $isUseOldValue = false)
    {
        $joinFieldName = $this->getFieldByColumn($tableJoin->columnRef, $tableJoin->table);
        $joinField = $this->varValue[$joinFieldName];
        $rhs = $isUseOldValue ? $joinField->oldValue : $joinField->value;
        $retStr = $tableJoin->column . "='" . $rhs . "'";
        return $retStr;
    }