sqlserver里循环调用

declare @T1 Int

select @T1=Pm_PListID from PmLists  where Pm_ListID=684
while exists(select 1 from PmLists where Pm_listid=@T1 and Pm_PListID>0)
  begin
  select @T1=Pm_PListID from PmLists  where Pm_ListID=@T1
  end

select @T1 as TmpField