Dynamic row range when calculating moving sum/average using window functions (SQL Server)

Question

I\'m currently working on a sample script which allows me to calculate the sum of the previous two rows and the current row. However, I would like to make the number \'2\' a

Answer 1

DECLARE @test VARCHAR = 1
DECLARE @sqlCommand VARCHAR(1000)
DECLARE @myTable TABLE  (myValue INT)

INSERT INTO @myTable ( myValue ) VALUES  ( 5)
INSERT INTO @myTable ( myValue ) VALUES  ( 6)
INSERT INTO @myTable ( myValue ) VALUES  ( 7)
INSERT INTO @myTable ( myValue ) VALUES  ( 8)
INSERT INTO @myTable ( myValue ) VALUES  ( 9)
INSERT INTO @myTable ( myValue ) VALUES  ( 10)

SET @sqlCommand = 'SELECT SUM(myValue) OVER (ORDER BY myValue ROWS BETWEEN ' + @test + ' PRECEDING AND CURRENT ROW)
                  FROM #temp'

EXEC (@sqlCommand)