SELECT * FROM (
select a.topicID,a.topicTitle,a.playerUID,b.nickName as nickName1,a.sectionID,c.sectionName,CONVERT(varchar(19),a.createTime,120) as createTime,a.isBest,a.isTop,a.isSys,d.nickName as nickName2,isnull(a.lastreplyUID,0) as lastreplyUID,CONVERT(varchar(19),a.lastreplyTime,120) as lastreplyTime,a.viewNum,a.replyNum,b.headIcon,d.headIcon as headIcon2,a.abstract,datediff(mi,a.createTime,getdate()) as isNews,TitleColor,'' TitleColorStr, ROW_NUMBER() OVER( order by a.issys desc,a.istop desc, isnull(a.lastreplytime,a.createtime) desc) as _rownum
FROM tb_forumtopic a inner join tb_playerinfo b on a.playeruid=b.playeruid inner join tb_forumsection c on a.sectionid=c.sectionid left join tb_playerinfo d on a.lastreplyuid=d.playeruid  
where (a.status=1 and c.status=1 and c.type=1 and a.sectionid in
(select sectionid from tb_forumsection where parentid=84)) or ( a.status=1 and c.status=1 and a.issys=1 )) as tab
WHERE _rownum between 1 and 25 order by _rownum asc