SQL学习-随机数，存储过程

USE bankDB
GO
SET NOCOUNT ON
--建存储过程pro_randCardID

IF EXISTS(SELECT * FROM sysobjects WHERE name='proc_randCardID')
 DROP proc proc_randCardID
GO
CREATE PROC proc_randCardID
@randCardID char(19) OUTPUT
AS
DECLARE @r numeric(15,8)

SELECT @r=RAND(
(DATEPART(mm,GETDATE())*100000)+
(DATEPART(ss,GETDATE())*1000)+
 DATEPART(ms,GETDATE())
)

SET @randCardID='1010 3576 '+SUBSTRING(convert(varchar(15),@r),3,4)+' '+SUBSTRING(convert(varchar(15),@r),7,4)
GO

DECLARE @mycardID char(19)
EXEC proc_randCardID @mycardID  OUTPUT
print '产生的随机卡号为:'+@mycardID