SQL Server User-defined Function Create and Call 與Stored Procedures 不同

1.創建方法:

1.1 Function

CREATE FUNCTION [OWNER].[FUNCTION NAME] (PARAMETER LIST)

RETURNS (return_type_spec) AS

BEGIN

(FUNCTION BODY)

END

例1:去除第一位為'0'的Function(LtrimZero)

CREATE FUNCTION dbo.LtrimZero(@d nvarchar(15))

RETURNS nvarchar(15) AS

BEGIN

WHILE (SUBSTRING(@d,1,1) = '0')

BEGIN

SET @d = SUBSTRING(@d, 2, LEN(@d) -1)

END

RETURN @d

END

例2:日期轉換成字符串Function(Date2String)

CREATE FUNCTION dbo.Date2String(@d AS nvarchar(10)) --增加長度8-->10 (20080101-->2008/01/01)

RETURNS nvarchar(10) AS

BEGIN

IF @d='00000000'

SET @d=''

ELSE

SET @d=SUBSTRING(@d,1,4) + '/' + SUBSTRING(@d,5,2) + '/' + SUBSTRING(@d,7,2)

RETURN @d

END

1.2 Procedures

CREATE PROCEDURE [OWNER].[PROCEDURE NAME] AS

例1:Procedures(Check_Rule)

CREATE PROCEDURE dbo.Check_Rule

(

@username nvarchar(20),

@password nvarchar(100),

@RMSG nvarchar(100) OUTPUT

)

AS

BEGIN

IF EXISTS(SELECT lsttime FROM tblRule WHERE username=@username AND password=@password)

BEGIN

SET @RMSG=''

UPDATE tblRule SET lsttime=GETDATE() WHERE username=@username

END

ELSE

SET @RMSG='Username or Password not correct !'

END

GO

例2:Procedures(UPDATE_tblRule)

CREATE PROCEDURE dbo.UPDATE_tblRule

(

@username nvarchar(20),

@password nvarchar(100),

@newpsw nvarchar(100),

@RMSG nvarchar(100) OUTPUT

)

AS

DECLARE @FLAG int

BEGIN

IF EXISTS(SELECT password FROM tblRule WHERE username=@username)

SET @FLAG=0

ELSE

SELECT @FLAG=-1, @RMSG='Username not correct !'

IF @FLAG=0

BEGIN

IF EXISTS(SELECT password FROM tblRule WHERE username=@username AND password=@password)

SET @FLAG=1

ELSE

SET @RMSG='Old Password not corrent!'

END

IF @FLAG=1

BEGIN

UPDATE tblRule SET password=@newpsw WHERE username=@username

SET @RMSG='Password Change success!'

END

END

GO

2.Call

2.1 Function: (LtrimZero,Date2String)

SELECT dbo.LtrimZero(Field),dbo. Date2String(Field) FROM TABLE

2.2 Procedures:(Check_Rule)

declare @P1 nvarchar(100)

exec Check_Rule @username = N'user', @password = N'psw', @RMSG = @P1 output

select @P1