INSERT INTO MIT_Vp
                      (Raggr, code, descr, [Sale date], Sign, QTA, Mese, Anno)
SELECT     somma.Raggr, somma.code, somma.descr, Vp.[Sale date], Vp.Sign, SUM(Vp.[Sale quantity UMB]) AS QTA, 
                      SUBSTRING(Vp.[Sale date], 3, 2) AS Mese, SUBSTRING(Vp.[Sale date], 5, 4) AS Anno
FROM         somma INNER JOIN
                      Vp ON somma.code = Vp.[Sap Product code]
GROUP BY somma.Raggr, somma.code, somma.descr, Vp.[Sale date], Vp.Sign