thank you for your replies. I wiil read them.

how about something like the following(using CTE):

declare @dataBegin datetime;

declare @dataEnd datetime;

set @dataEnd = '21/05/2013';

set @dataBegin = DATEADD(month,-11, @dataEnd) - (DAY(@dataEnd)-1);

set @dataEnd = DATEADD(month,1, @dataEnd) - (DAY(@dataEnd));

WITH dates AS

(

SELECT CAST(@dataBegin AS DATETIME) 'date'

UNION ALL

SELECT DATEADD(MONTH, 1, t.date)

FROM dates t

WHERE DATEADD(month, 1, t.date) <= @dataEnd

)

select month(dates.date) as mese, YEAR(dates.date) as anno,department

from dates

,

(

SELECT distinct department

FROM T1

) t2

the result is that i have all the dates i need with the departments but i need to join this result with

SELECT department,SUM(totalsales) AS totsales, MONTH(dateofsale) as month, YEAR(dateofsale) as year

FROM T1

WHERE dateofsale >= @dataBegin AND dateofsale< @dataEnd

GROUP BY department,MONTH(dateofsale), YEAR(dateofsale)

ORDER BY department,MONTH(dateofsale), YEAR(dateofsale)

the problem is that i cant do this join...

any idea?

thank's again