IF OBJECT$\_$ID $($N$\text{'}$dbo$.$ufnGetInventoryStock', N$\text{'}$FN$\text{'})$ IS NOT NULL

DROP FUNCTION ufnGetInventoryStock;

GO

CREATE FUNCTION dbo.ufnGetInventoryStock$($@ProductID int$)$

RETURNS int

AS

$--$ Returns the stock level for the product.

BEGIN

DECLARE @ret int;

SELECT @ret $=$ SUM$($p$.$Quantity$)$

FROM Production.ProductInventory p

WHERE p$.$ProductID $=$ @ProductID

AND p$.$LocationID $=\text{'}6\text{'}$;

IF $($@ret IS NULL$)$

SET @ret $=0$;

RETURN @ret;

END; covert this procedure into function