sql 流水号获取

经常用到产生订单号等流水单号的场景，sqlserver实现流水号，如下：

表tb_b_Seq(流水号表)：

CREATE TABLE tb_b_Seq(
Year int ,--年份
Month int,--月份
Attr varchar(50),--属性
Seq int--流水号
) 

获取流水号，通过存储过程：

create Proc GetSeq (
@attr varchar(50),
@year int,
@month int,
@Return int output )
As
set @Return=(select top 1 Seq from tb_b_Seq where Attr=@attr and MONTH=@month and YEAR=@year)
if(@Return is null)
begin
    set @Return=1
    insert into FMDS_tb_b_Seq (Attr,Year,Month,Seq) values (@attr,@year,@month,@Return)
end
else
begin
    set @Return=@Return+1
    update FMDS_tb_b_Seq set Seq=@Return where Attr=@attr and MONTH=@month and YEAR=@year
end

测试：

declare @ret int
exec GetSeq 'Contract',2017,10,@ret
print @ret