private function _prepareJoin() 
	{
		$sQuery = '';

		if (is_array($this->_aJoin) && count($this->_aJoin) > 0) {

			foreach ($this->_aJoin as $sKey => $aValue) {

				if (isset($aValue['type']) && $aValue['type'] == 'left') {

					$sQuery .= " LEFT JOIN `".$aValue['table']."` ";
				}
				else {

					$sQuery .= " INNER JOIN `".$aValue['table']."` ";
				}

				if (isset($aValue['as']) && $aValue['as']) {

					$sQuery .= " AS ".$aValue['as']." ";
				}
				else {

					$sQuery .= " AS t".$this->_iAlias." ";
					$this->_iAlias++;
				}

				$sQuery .= " ON ".$aValue['left_field']." =  ".$aValue['right_field']." ";
			}
		}

		return $sQuery;
	}