%tWHERE1%i里面的%t和%i，是如何控制的。

public function fetch_all_by_search($tableid, $tid = null, $keywords = null, $invisible = null, $fid = null, $authorid = null, $author = null, $starttime = null, $endtime = null, $useip = null, $first = null, $start = null, $limit = null) {
		$sql = '';
		$sql .= $tid ? ' AND '.DB::field('tid', $tid) : '';
		$sql .= $authorid ? ' AND '.DB::field('authorid', $authorid) : '';
		$sql .= $invisible !== null ? ' AND '.DB::field('invisible', $invisible) : '';
		$sql .= $first !== null ? ' AND '.DB::field('first', $first) : '';
		$sql .= $fid ? ' AND '.DB::field('fid', $fid) : '';
		$sql .= $author ? ' AND '.DB::field('author', $author) : '';
		$sql .= $starttime ? ' AND '.DB::field('dateline', $starttime, '>=') : '';
		$sql .= $endtime ? ' AND '.DB::field('dateline', $endtime, '<') : '';
		$sql .= $useip ? ' AND '.DB::field('useip', $useip, 'like') : '';
		if(trim($keywords)) {
			$sqlkeywords = $or = '';
			foreach(explode(',', str_replace(' ', '', $keywords)) as $keyword) {
				$keyword = addslashes($keyword);
				$sqlkeywords .= " $or message LIKE '%$keyword%'";
				$or = 'OR';
			}
			$sql .= " AND ($sqlkeywords)";
		}
		if($sql) {
			return DB::fetch_all('SELECT * FROM %t WHERE 1 %i ORDER BY dateline DESC %i', array(self::get_tablename($tableid), $sql, DB::limit($start, $limit)));
		} else {
			return array();
		}
	}