Retrieving value from EXEC(@sql)
SELECT top (value) field, field2 FROM table

SELECT @first = min(field2) FROM (SELECT top (value) field, field2 FROM table)

DECLARE @RowCount int -- =25 -- sql server 2008 allows to assign when declaring
SELECT @RowCount = 25

SELECT TOP (@RowCount) * FROM table1

DECLARE @RowCount int
SELECT @RowCount = 25

SET ROWCOUNT @RowCount
SELECT  * FROM table1

SET ROWCOUNT 0  -- make sure to set back to 0 otherwise
                -- queries below will return 25 rows

declare @top int = 10

select top (@top) field, field2 from table