求一条关于时间条件的语句

Question

大家好！
     我有一个表TableTime如下：
  Barcode        Createdate               Result
   KK1     2007-09-23 01:21:33             NG
   KK1     2007-09-23 02:22:33             NG
   KK1     2007-09-23 04:36:21             NG
   KK2     2007-09-23 05:36:21             OK
   KK2     2007-09-23 06:36:21             OK
   KK3     2007-09-23 04:34:21             NG
   KK1     2007-09-23 04:58:21             OK
   KK3     2007-09-23 08:34:21             NG
........
我想找出数据库中同一条码的时间最后的记录，
如表中的结果就应该是：
KK1     2007-09-23 04:58:21             OK
KK2     2007-09-23 06:36:21             OK
KK3     2007-09-23 08:34:21             NG请问这个语句该怎么写？

Answer 1

select * from TableTime
where Barcode,Createdate in (
select Barcode ,max(Createdate)
from TableTime
group by Barcode )

Answer 2

这个语句好像有问题，另外：如果找最后结果为NG的记录呢？
即上面查询的结果是
KK3     2007-09-23 08:34:21             NG

Answer 3

select a.*
from
tabletime a,
(select Barcode ,max(Createdate) creatdate
from TableTime
group by Barcode
) b
where
a.Barcode=b.Barcode
and a.Createdate=b.Createdate

Answer 4

 select *
   from (
         select tt.*,
                row_number() over(partition by Barcode order by Createdate desc) as rn
           from TableTime tt
        )zz
  where rn = 1;-------------------------------------------------------------------------如果是NG的情况:   select *
   from (
         select tt.*,
                row_number() over(partition by Barcode order by Createdate desc) as rn
           from TableTime tt
        )zz
  where rn = 1
    and tt.Result = 'NG';

Answer 5

create table  TableTime(Barcode varchar2(10), Createdate varchar2(50),  Result varchar2(50));
insert into TableTime
select 'KK1','2007-09-23 01:21:33','NG' from  dual
union all
select 'KK1','2007-09-23 02:22:33','NG' from  dual
union all
select 'KK1','2007-09-23 04:36:21','NG' from  dual
union all
select 'KK2','2007-09-23 05:36:21','OK' from  dual
union all
select 'KK2','2007-09-23 06:36:21','OK' from  dual
union all
select 'KK3','2007-09-23 04:34:21','NG' from  dual
union all
select 'KK1','2007-09-23 04:58:21','OK' from  dual
union all
select 'KK3','2007-09-23 08:34:21','NG' from  dual;
select * from TableTime A where not exists(select 1 from  TableTime T where A.Barcode=T.Barcode and A.Createdate<T.Createdate)
order by A.barcode
测试结果如下：
KK1     2007-09-23 04:58:21             OK
KK2     2007-09-23 06:36:21             OK
KK3     2007-09-23 08:34:21             NG
楼主测试下