Select one line of each code

I've got a Table that stores messages like this: codMsg, message, anotherCod

1, 'hi', 1
2, 'hello', 1
3, 'wasup', 1
4, 'yo', 2
5, 'yeah', 2
6, 'gogogo', 3

I was wondering if is possible to select top 1 of each anotherCod

Wh开发者_运维知识库at I expect:

1, 'hi', 1
4, 'yo', 2
6, 'gogogo', 3

I want the whole line, not just the number of the anotherCod, so group by should not work

select mytable.*
from mytable
join (select min(codMsg) as codMsg, anotherCod from mytable group by 2) x    
    on mytable.codMsg = x.codMsg

SQL Server 2005+, Oracle :

SELECT codMsg, 
       message, 
       anotherCod
FROM
(
    SELECT codMsg, 
           message, 
           anotherCod,  
           RANK() OVER (PARTITION BY anotherCod ORDER BY codMsg ASC) AS Rank
    FROM mytable
) tmp
WHERE Rank = 1

SELECT
  *
FROM
  myTable
WHERE
  codMSG = (SELECT MIN(codMsg) FROM myTable AS lookup WHERE anotherCod = myTable.anotherCod)