详细讲解SQL Server中“函数”的两种用法

　　CREATE FUNCTION [DBO].[FUN_GETTIME] (@TASKPHASEID INT) 
　　RETURNS FLOAT AS 
　　BEGIN 
　　DECLARE @TASKID INT, 

　　@HOUR FLOAT, 
　　@PERCENT FLOAT, 
　　@RETURN FLOAT 
　　IF @TASKPHASEID IS NULL 
　　BEGIN 
　　RETURN(0.0) 
　　END 
　　SELECT @TASKID=TASKID,@PERCENT=ISNULL(WORKPERCENT,0)/100 
　　FROM TABLETASKPHASE 
　　WHERE ID=@TASKPHASEID 
　　SELECT @HOUR=ISNULL(TASKTIME,0) FROM TABLETASK 
　　WHERE ID=@TASKID 
　　SET @RETURN=@HOUR*@PERCENT 
　　RETURN (@RETURN) 
　　END

　　CREATE PROCEDURE [DBO].[PROC_CALCCA] 
　　@ROID INT 
　　AS 
　　BEGIN 
　　DECLARE @CA FLOAT 
　　UPDATE TABLEFMECA 
　　SET 
　　Cvalue_M= ISNULL(MODERATE,0)*ISNULL
(FMERATE,0)*ISNULL(B.BASFAILURERATE,0)*[DBO].[FUN_GETTIME](C.ID) 
　　FROM TABLEFMECA ,TABLERELATION B,TABLETASKPHASE C 
　　WHERE ROID=@ROID AND TASKPHASEID=C.ID AND B.ID=@ROID 
　　SELECT @CA=SUM(ISNULL(Cvalue_M,0)) FROM TABLEFMECA WHERE ROID=@ROID 
　　UPDATE TABLERELATION 
　　SET CRITICALITY=@CA 
　　WHERE ID=@ROID 
　　END 
　　GO

SUM ( [ ALL | DISTINCT ] expression )
expression