select t.riqi,t.maxonlinenum,t.maxolinetime,a.activenum from (
select convert(nvarchar,logtime,23)as riqi,max(在线人数)as maxonlinenum,convert(nvarchar,logtime,20)as maxolinetime, row_number() over(partition by convert(nvarchar,logtime,23) order by 在线人数 desc) rn from table where convert(nvarchar,logtime,20)>='2015-08-13' and convert(nvarchar,logtime,20)<'2015-08-13 24:00:00' and svrid = '100' and 在线人数 > 0 group by convert(nvarchar,logtime,23),在线人数,convert(nvarchar,logtime,20)) t inner join (select CONVERT(varchar(255),CONVERT(datetime,logtime),23) as riqi,count(distinct 账号)as activenum from table where logtime>='2015-08-13' and logtime<'2015-08-13 24:00:00' group by CONVERT(varchar(255),CONVERT(datetime,logtime),23))as a on t.riqi=a.riqi where t.rn <=1