with t1 as(
select Row_number() over(order by id) as B,fid  from Order_Main 
where ov_bid like'%是%'  and OV_CaoDan<>'废单'  and  OV_CaoDan<>'签单'
and fstype<>3 and ftradetype in (2))

select  fid      
from t1   where B in( cast(ceiling(rand() * (select count(*) from t1)  )as int)  )

select  top fid      
from t1   
order by newid()

------解决方案--------------------
直接用newid()嘛，还编号干啥
SQL code
select top1 fid  from Order_Main 
where ov_bid like'%是%'  and OV_CaoDan<>'废单'  
  and  OV_CaoDan<>'签单'
and fstype<>3 and ftradetype in (2))
order by newid()

------解决方案--------------------
探讨

问一下， 如果 跑出空值，就 返回 重新 跑， 直到 跑出值， 这个怎么做