--create a table for some sample data

IF OBJECT_ID('tempdb..#TempTable') IS NOT NULL

DROP TABLE #TempTable

CREATE TABLE #TempTable (

[ID] INT NOT NULL,

[Col1] INT NULL,

[Col2] INT NULL,

PRIMARY KEY (ID))

--insert random numbers with a few nulls tossed in

INSERT INTO #TempTable

SELECT 1,ABS(CAST(NEWID() AS BINARY(6))%10)+1,ABS(CAST(NEWID() AS BINARY(6))%10)+1

UNION

SELECT 2,ABS(CAST(NEWID() AS BINARY(6))%10)+1,ABS(CAST(NEWID() AS BINARY(6))%10)+1

UNION

SELECT 3,NULL,ABS(CAST(NEWID() AS BINARY(6))%10)+1

UNION

SELECT 4,ABS(CAST(NEWID() AS BINARY(6))%10)+1,ABS(CAST(NEWID() AS BINARY(6))%10)+1

UNION

SELECT 5,ABS(CAST(NEWID() AS BINARY(6))%10)+1,NULL

UNION

SELECT 6,ABS(CAST(NEWID() AS BINARY(6))%10)+1,ABS(CAST(NEWID() AS BINARY(6))%10)+1

--raw table

SELECT * FROM #TempTable ORDER BY ID

--Col1+Col2 = Col3

SELECT

ID

,Col1

,Col2

,Col3 = ISNULL(Col1,0) + ISNULL(Col2,0)

FROM

#TempTable

ORDER BY

ID