select * from Table a where 
exists(select * from Table where a.CARID =CARID  having a.CREATETIME =max(CREATETIME) )
 and LINEID ='302' and UPDOWN = 1

select top 1 * 
from Table a 
where 
    LINEID ='302' 
    and UPDOWN = 1
order by CREATETIME desc

------解决方案--------------------
SQL code

select * from Table a where 
exists(select * from Table where a.CARID =CARID  having a.CREATETIME =max(CREATETIME) )
 and LINEID ='302' and UPDOWN = 1


1、首先 把你的 * 换成具体的字段。
2、第二个 *  改用一个字段（CARID）或直接写 1
3、就是在你的条件上 建索引
4、如果查询所得的列个数少，再建该列的 包含索引

------解决方案--------------------
SQL code

select * from Table a where 
exists(select * from Table where a.CARID =CARID  having a.CREATETIME =max(CREATETIME) )
 and LINEID ='302' and UPDOWN = 1

--楼主为何写子查询呢

select --所有字段
from table a 
where 
  createtime=max(createtieme)
and lineid='302' and updown=1
order by CREATETIME desc

------解决方案--------------------
select * from Table a where  
exists(select * from Table where a.CARID =CARID  having a.CREATETIME =max(CREATETIME) )
  and LINEID ='302' and UPDOWN = 1

select * from  
(
select *,id=row_number () over (partition by  CARID order by CREATETIME desc)
from table
where LINEID ='302' and UPDOWN = 1
) K
where id=1

------解决方案--------------------
SQL code
--try
select * from Table a where 
not  exists(select * from Table where a.CARID =CARID  and a.CREATETIME<CREATETIME )
and LINEID ='302' and UPDOWN = 1

------解决方案--------------------
SQL code


select * from Table a 
where a.CREATETIME = (select max(b.CREATETIME) from Table b where a.CARID =b.CARID)
 and LINEID ='302' and UPDOWN = 1

/*这样应该可以了*/