判断临时表是否存在，存在先删除

    if object_id('tempdb..#tmp1') is not null
    begin
      truncate table #tmp1
      drop table #tmp1                                                           
    end

                                                                               
    if object_id('tempdb..#tmp2') is not null
    begin
      truncate table #tmp2
      drop table #tmp2                                                       
    end