SQL里面，有时候会用到exists或者not exists。

select * from yb t1 where not exists(select 1 from yb t2 where trunc(t1.yubaodate,'dd')=trunc(t2.yubaodate,'dd') and t1.yubaotype=t2.yubaotype and t1.id<t2.id)

order by id desc; 

然后，LINQ里怎么用？

var t1 = ybRepository.GetAll();

var t2 = ybRepository.GetAll();

var list = from s in t1

           where !t2.Any(ss => ss.YUBAODATE.Date == s.YUBAODATE.Date

            && ss.YuBaoType == s.YuBaoType

            && ss.ID > s.ID)

           select s;

万幸，fluently nhibernate支持这种写法。