无法在 R 中运行 SQLDF 查询，语法错误

Question

RollFwd <- sqldf(" SELECT 
                  Master_ID.InventoryId, 
                  BegInv_dplyr.OnHand AS BegInv_OnHand,
                  PurchSummaryTable.PurchaseQuantity AS Purch_Quantity,
                  PurchSummaryTable.sum(Dollars) AS Purchase_Dollars,
                  SalesSummaryTable.sum(SalesQuantity) AS Sales_Quantity,
                  SalesSummaryTable.sum(SalesDollars) AS Sales_Dollars,
                  EndInv_dplyr.EndInv AS EndInv_OnHand,
 
                  FROM Master_ID 
 
                  LEFT JOIN
                  BegInv_dplyr on Master_ID.InventoryId = BegInv_dplyr.InventoryId
                  LEFT JOIN
                  PurchSummaryTable on Master_ID.InventoryId = PurchSummaryTable.InventoryID
                  LEFT JOIN
                  SalesSummaryTable on Master_ID.InventoryId = SalesSummaryTable.InventoryID
                  LEFT JOIN
                  EndInv_dplyr on Master_ID.InventoryId  = EndInv_dplyr.InventoryId
 
                  GROUP BY Master_ID.Inventory.Id ")
RollFwd[is.na(RollFwd)] = 0

尝试查询几个表，无法找出导致语法错误的原因。我认为这是一个逗号问题，但似乎无法正常工作

Error: near "(": syntax error