函数如下

CREATE FUNCTION StockBalance_AmountIn(@SortID int) 
 RETURNS numeric(18,4)
AS 
BEGIN
 Declare @dblReturn numeric(18,4)
 
 Select @dblReturn = SUM(AmountCurrentMonthIn) From AT_Materiel_StockBalance Where SortID = @SortID
 Return (@dblReturn)
END

调用方法
select dbo.StockBalance_AmountIn(2523)

这里头需要加dbo