Question

I have a table:

id  cod_pr      Date        nr
-------------------------------
1     22     12.10.2012     2
2     25     12.10.2012     3
3     22     12.11.2012     5
4     25     12.11.2012     2
5     22     12.12.2012     4
6     23     12.10.2012     3

How kan I select only max Date from each cod_pr?

Answer 1

If you want all columns, you can use ROW_NUMBER in a CTE:

WITH CTE AS
(
   SELECT id,cod_pr,Date,nr,
      ROW_NUMBER() OVER (PARTITION BY cod_pr ORDER BY Date DESC) AS RN
   FROM dbo.Table
)
SELECT id,cod_pr,Date,nr, FROM CTE WHERE RN = 1

Otherwise you can simply use GROUP BY

SELECT cod_pr, MAX(Date) AS MaxDate
FROM dbo.Table
GROUP BY cod_pr