先分组，再合计
SELECT [Product BOM].[Package code], [Product BOM].[Launch _Season], [Product BOM].[Package category], [Product BOM].[Package description], [Product BOM].[Package supplier], Sum([Usage]*[Product forecast!P2016]) AS 2016demand, Sum([Usage]*[Product forecast!P2017]) AS 2017demand, Sum([Usage]*[Product forecast!P2018]) AS 2018demand
FROM ([Product FOB] INNER JOIN ([Product BOM] INNER JOIN [Product forecast] ON [Product BOM].[Style number] = [Product forecast].[Style number]) ON [Product FOB].[Style number] = [Product forecast].[Style number]) INNER JOIN [Package FOB] ON [Product BOM].[Package code] = [Package FOB].[Package code]
GROUP BY [Product BOM].[Package code], [Product BOM].[Launch _Season], [Product BOM].[Package category], [Product BOM].[Package description], [Product BOM].[Package supplier];
