ms-sql 2000 怎么取上个月的月份
我想建一个表：

if exists (select * from dbo.sysobjects where id = object_id(N '[dbo].[aa] ') and OBJECTPROPERTY(id, N 'IsUserTable ') = 1)
drop table [dbo].[aa]


go


CREATE TABLE [dbo].[aa] (
[市名] [nvarchar] (50) COLLATE Chinese_PRC_CI_AS NOT NULL
[钱数] [nvarchar] (50) COLLATE Chinese_PRC_CI_AS NULL ,
[录入时间] [nvarchar] (50) COLLATE Chinese_PRC_CI_AS NULL
) ON [PRIMARY]
然后再以城市名+上月的月份来命名该表

select object_id( 'aa ')
go
declare @mm nvarchar(50), @dd nvarchar(50), @cc nvarchar(50),@yy nvarchar(50)
select @cc= 'beijing_ '
select @yy=datename(year,getdate())
select @mm =datename(month,getdate())-1
select @dd=@cc+@yy+@mm
select @dd
exec sp_rename 'aa ',@dd
go

小弟刚学，这样在1月的时候就不对了,望大家给指导下怎么解决这问题


[解决办法]
select object_id( 'aa ')
go
declare @mm nvarchar(50), @dd nvarchar(50), @cc nvarchar(50),@yy nvarchar(50)
select @cc= 'beijing_ '
select @yy=datename(year,getdate())
select @mm =cast(month(getdate())-1 as varchar)
select @dd=@cc+@yy+@mm
select @dd
exec sp_rename 'aa ',@dd
go
[解决办法]
declare @year as int
declare @month as int

set @month = month(getdate())

if @month = 1
begin
set @month = 12
set @year = year(getdate()) - 1
end
else
begin
set @month = @month - 1
set @year = year(getdate())
end