两种SQL Server 2000里函数的用法

2012-4-27 20:54:00 来源:网络转载 浏览:235
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。本文就为大家介绍一下两种SQL Server 2000里函数的用法。

 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:

  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

  调用函数的存储过程部分

  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

  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:

  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 ID=@QUALITYID

  SELECT @G=ISNULL(FRATE_G,0) FROM TABLEFAILURERATE

  WHERE (SUBKINDID=@PARTID) AND( ENID=@ENID) AND ( DATASOURCEID=@SOURCEID) AND( ( (ISNULL(MINCOUNT,0)<=ISNULL(@COUNT,0)) AND ( ISNULL(MAXCOUNT,0)>=ISNULL(@COUNT,0)))

  OR(ISNULL(@COUNT,0)>ISNULL(MAXCOUNT,0)))

  SET @RATE=ISNULL(@QXS*@G,0)

  RETURN (@RATE)

  END

  调用函数的存储过程部分:

  CREATE PROC PROC_FAULTRATE

  @PARTID INTEGER, @QUALITYID INTEGER, @SOURCEID INTEGER, @COUNT INTEGER, @ROID INT, @GRADE INT,@RATE FLOAT=0 OUTPUTAS

  BEGIN

  DECLARE

  @TASKID INT

  SET @RATE=0.0

  SELECT @TASKID=ISNULL(TASKPROID,-1) FROM TABLERELATION WHERE ID=(SELECT PID FROM TABLERELATION WHERE ID=@ROID)

  IF (@TASKID=-1) OR(@GRADE=1) BEGIN

  SET @RATE=0

  RETURN

  END

  SELECT @RATE=SUM([DBO].[FUN_RATE] (@PARTID,ENID,@SOURCEID, @QUALITYID,@COUNT) *ISNULL(WORKPERCENT,0)/100.0)

  FROM TABLETASKPHASE

  WHERE TASKID=@TASKID

  END

  GO

  函数还可以返回表等,希望大家一起讨论sqlserver里函数的妙用。

(0)
(0)