inserting from a table to another table and activeting trigger

INSERT INTO SaleItem (ProdId, SaleQuantity) SELECT ProdId, BasketProdQuantity FROM Basket;

CREATE TRIGGER TRG_Stock_Decrease
    ON SaleItem
AFTER INSERT
AS
DECLARE @ProdId INT
DECLARE @SaleQuantity INT
SELECT @ProdId=ProdId,@SaleQuantity=SaleQuantity FROM inserted
UPDATE Product SET ProdStockQuantity=ProdStockQuantity-@SaleQuantity WHERE ProdId=@ProdId
UPDATE Product SET ProdNoOfSold =ProdNoOfSold+@SaleQuantity WHERE ProdId=@ProdId
DELETE FROM Basket Where ProdId = @ProdId

when I insert datas from Basket to SaleItem it works well. but trigger only work for first id that inserted. how can make it work for all ids?