关于一个 SQL 随机 函数的有关问题

关于一个 SQL 随机 函数的问题

SQL code

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)  )

SQL code

select  top fid      from t1   order by newid()
[解决办法]
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()
[解决办法]
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