SQL Server里函数的两种用法(可以代替游标)
1. 因为update里不能用存储过程，然而要根据更新表的某些字段还要进行计算。我们常常采用游标的方法，这里用函数的方法实现。
函数部分：
以下是引用片段：
CREATE FUNCTION [DBO].[FUN_GETTIME] (@TASKPHASEID INT)
RETURNS FLOAT AS
BEGIN
DECLARE @TASKID INT,
[email protected] FLOAT,
[email protected] FLOAT,
[email protected] FLOAT
IF @TASKPHASEID IS NULL
BEGIN
RETURN(0.0)
END
SELECT @TASKID=TASKID,@PERCENT=ISNULL(WORKPERCENT,0)/100
FROM TABLETASKPHASE
WHERE [email protected]
SELECT @HOUR=ISNULL(TASKTIME,0) FROM TABLETASK
WHERE [email protected]
SET @[email protected][email protected]
RETURN (@RETURN)
END
调用函数的存储过程部分
以下是引用片段：
CREATE PROCEDURE [DBO].[PROC_CALCCA]
[email protected] 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 [email protected] AND TASKPHASEID=C.ID AND [email protected]
SELECT @CA=SUM(ISNULL(Cvalue_M,0)) FROM TABLEFMECA WHERE [email protected]
UPDATE TABLERELATION
SET [email protected]
WHERE [email protected]
END
GO
2. 我们要根据某表的某些记录，先计算后求和，因为无法存储中间值，平时我们也用游标的方法进行计算。但sqlserver2000里支持
SUM ( [ ALL | DISTINCT ] expression )
expression
是常量、列或函数，或者是算术、按位与字符串等运算符的任意组合。因此我们可以利用这一功能。
函数部分：
以下是引用片段：
CREATE FUNCTION [DBO].[FUN_RATE] (@PARTID INT,@ENID INT,@SOURCEID INT, @QUALITYID INT,@COUNT INT)
RETURNS FLOAT AS
BEGIN
DECLARE @QXS FLOAT, @G FLOAT, @RATE FLOAT
IF (@ENID=NULL) OR (@PARTID=NULL) OR (@SOURCEID=NULL) OR (@QUALITYID=NULL)
BEGIN
RETURN(0.0)
END
SELECT @QXS= ISNULL(XS,0) FROM TABLEQUALITY WHERE [email protected]
SELECT @G=ISNULL(FRATE_G,0) FROM TABLEFAILURERATE
WHERE ([email protected]) AND( [email protected]) AND ( [email protected]) AND( ( (ISNULL(MINCOUNT,0) <=ISNULL(@COUNT,0)) AND ( ISNULL(MAXCOUNT,0)> =ISNULL(@COUNT,0)))
OR(ISNULL(@COUNT,0)> ISNULL(MAXCOUNT,0)))
SET @RATE=ISNULL(@[email protected],0)
RETURN (@RATE)
END
调用函数的存储过程部分：
以下是引用片段：
CREATE PROC PROC_FAULTRATE
[email protected] INTEGER, @QUALITYID INTEGER, @SOURCEID INTEGER, @COUNT INTEGER, @ROID INT, @GRADE INT,@RATE FLOAT=0 OUTPUTAS
BEGIN
DECLARE
[email protected] INT
SET @RATE=0.0
SELECT @TASKID=ISNULL(TASKPROID,-1) FROM TABLERELATION WHERE ID=(SELECT PID FROM TABLERELATION WHERE [email protected])