function SelectLimit($sql, $nrows=-1, $offset=-1, $inputarr=false, $secs=0)
	{
		$offsetStr =($offset>=0) ? "$offset," : '';
		// jason judge, see http://phplens.com/lens/lensforum/msgs.php?id=9220
		if ($nrows < 0) {
			$nrows = '18446744073709551615';
		}

		if ($secs) {
			$rs = $this->CacheExecute($secs, $sql . " LIMIT $offsetStr$nrows", $inputarr);
		} else {
			$rs = $this->Execute($sql . " LIMIT $offsetStr$nrows", $inputarr);
		}
		return $rs;
	}