求一个SQL语句,感觉比较复杂

Question

现有一张表
create table T
(
  CHTRCD CHAR(16) not null,
  SRDT   DATE not null,
  JMDS   NUMBER(7,1) not null,
)查询条件为:chtrcd,jmds,srdt均不同,如果chtrcd和jmds相同则srdt时间最晚比如里面有这样几条记录
chtrcd                   srdt                 jmds
AAAAAA                   2005-05-01            11
AAAAAA                   2005-04-01            11
AAAAAA                   2005-05-01            12
BBBBBB                   2005-05-01            12
BBBBBB                   2005-04-01            14
BBBBBB                   2005-05-01            14我需要查询的结果为
AAAAAA                   2005-05-01            11
AAAAAA                   2005-05-01            12
BBBBBB                   2005-05-01            12
BBBBBB                   2005-05-01            14

Answer 1

select * from T where srdt=(select max(srdt) from T T1 where T1.chtrcd=T.chtrcd)

Answer 2

select CHTRCD,max( SRDT),JMDS from t group by CHTRCD,JMDS