不使用CTE也就是with因为限制太多，比如不能使用参数
declare @startId int
select @startId = id from externalstatus where statusname = @rootStatusName
declare @backtrace table(id int,lvl int)
declare @id int
set @id = @startId
declare @lvl int
set @lvl=0
insert @backtrace select id, @lvl from externalstatus where id = @id
while @@rowcount>0
begin
set @lvl=@lvl+1
insert @backtrace select [status].id, @lvl
from externalstatus [status],@backtrace backtrace
where [status].pid=backtrace.id
and backtrace.lvl=@lvl-1
end
