表变量，临时表

--表变量
update invent set goodInfo=null
declare @tmp_goods table(
    gno char(5)
)
insert into @tmp_goods select gno from invent group by gno

declare @gno char(6),@stno char(6),@gname varchar(255),@producer varchar(255)
while exists(select gno from @tmp_goods)
    begin
        set rowcount 1
        select @gno=gno from @tmp_goods
        select @gname=gname,@producer=producer from goods where gno=@gno;
        set rowcount 0
        update invent set goodInfo=@gname+'-'+@producer where gno=@gno
        
        delete from @tmp_goods where gno=@gno
    end

select * from invent

--临时表  放在dbtemp数据库中
if OBJECT_ID('tempdb.dbo.#tmp_inv','U') is not null
drop table #tmp_invent

方法1：
create table #tmp_inv(id int)
--方法2
select * into #tmp_inv from invent