SQL中唯一行的聚合

Question

I have the following table of unique rows:

Name        change  Number_of_Sales
Soby        2.22    8370
Sollerod    -1.06   11287
Sonderborg  2.60    6343
Sonderhald  11.43   1623
Sonderhald  10.93   2098

I want to select name and change , excluding duplicate Names, so that Sonderhald only occurs once. I want the Sonderhald with the maximum Number_of_Sales .

How can I do this in SQL Server?

Thanks

Answer 1

SELECT t.name, t.change, t.number_of_sales
FROM your_table t
INNER JOIN (
        SELECT tt.name, MAX(tt.number_of_sales) AS max_number_of_sales 
        FROM your_table tt 
        GROUP BY tt.name
    ) tm ON t.name = tm.name AND t.number_of_sales = tm.max_number_of_sales

Answer 2

You can use a common table expression to do this:

;
WITH    cte
          AS ( SELECT   Name,
                        Change,
                        Number_of_Sales,
                        ROW_NUMBER() OVER ( PARTITION BY name ORDER BY number_of_sales DESC ) AS RowNum
               FROM     your_table
             )
    SELECT  Name,
            Change,
            Number_of_Sales
    FROM    cte
    WHERE   RowNum = 1

http://technet.microsoft.com/en-us/library/ms190766%28v=sql.105%29.aspx