You were SO close...

SELECT

U.Num,

U.NAME,

[1] = SUM(CASE WHEN MONTH(W.WorkDay) = 1 THEN W.TimeWorked ELSE 0 END),

[2] = SUM(CASE WHEN MONTH(W.WorkDay) = 2 THEN W.TimeWorked ELSE 0 END),

[3] = SUM(CASE WHEN MONTH(W.WorkDay) = 3 THEN W.TimeWorked ELSE 0 END),

[4] = SUM(CASE WHEN MONTH(W.WorkDay) = 4 THEN W.TimeWorked ELSE 0 END),

[5] = SUM(CASE WHEN MONTH(W.WorkDay) = 5 THEN W.TimeWorked ELSE 0 END)

FROM #Users U INNER JOIN #Working W ON U.Num = W.Num

GROUP BY U.Num, U.Name;

You can learn more about this technique (cross tab) at the following link.

http://www.sqlservercentral.com/articles/T-SQL/63681/

And thank you VERY much for the test data setup and the sample code. It made helping you very easy to do. I wish more people would take the small bit of time.