php问题，跪求各位大牛指点迷津

<?phpif(!defined('in_discuz')) {	exit('access denied');}class plugin_qdkzcj {	function global_qdadd(){		global $_g;		$tablepre=$_g['config']['db']['1']['tablepre'];		@extract($_g['cache']['plugin']['qdkzcj']);						$_g['isqd']=$_g['qdday']=0;				$_g['todayq'] = db::result_first("select `todayq` from `{$tablepre}dsu_paulsignset` where `id` ='1' ");				if(!$_g['uid']) return '';				$qiandaodb = db::fetch_first("select time from ".db::table('dsu_paulsign')." where uid='$_g[uid]'");		$htime = dgmdate($_g['timestamp'], 'h',$var['tos']);		$tdtime=strtotime(date('y-m-d'));		if($qiandaodb['time']<$tdtime){			$_g['isqd']=0;		}else{			$_g['isqd']=1;		}		$_g['qdday']=db::result_first("select `lasted` from `{$tablepre}dsu_paulsign` where `uid` ='{$_g['uid']}' limit 0 , 1");		$_g['qmday']=db::result_first("select `mdays` from `{$tablepre}dsu_paulsign` where `uid` ='{$_g['uid']}' limit 0 , 1");		$_g['qtime']=db::result_first("select `time` from `{$tablepre}dsu_paulsign` where `uid` ='{$_g['uid']}' limit 0 , 1");				$_g['qqtime']=date('ymd',$_g['qtime'])==date('ymd',$_g['timestamp'])?date('h:i',$_g['qtime']):date('m-d',$_g['qtime']);			}}function qdbyuid($uid){	return db::result_first("select `lasted` from ".db::table("dsu_paulsign")." where `uid` ='{$uid}' limit 0 , 1");}function qdbyuser($user){	$user=addslashes($user);	$uid=db::result_first("select uid from ".db::table("common_member")." where username='$user' limit 1");	return db::result_first("select `lasted` from ".db::table("dsu_paulsign")." where `uid` ='{$uid}' limit 0 , 1");}?>