Which one is better for getting the last row of my table with linq to nhibernate?

Question

Which one is better for getting the last row of my table with linq to nhibernate? Why?

    internal Bill GetLastBill()
    {
        var q = from b in session.Linq<Bill>()
                select b;

        return q.OrderByDescending(x => x.Id).First();
    }

OR

    internal Bill GetLastBill()
    {
        long maxId = session.Linq<Bill>().Max(i => i.Id);

        var q = from b in session.Linq<Bill>()
                where b.Id == maxId
                select b;

        return q.First();
    }

You should a database profiler (or use NHProf) to see the generated query. They could both be using the same query. The only way to be sure is to profile it :) — tucaz, Jun 21 '11 at 18:41

score 3 · Accepted Answer · answered Jun 21 '11 at 18:35

3

Have you considered:

return session.Linq<Bill>().Last();

MSDN Reference

answered Jun 21 '11 at 18:35

lsuarez

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What is the generated sql query for this linq query? – masoud ramezani Jun 21 '11 at 19:12
1

Not working "The LastResultOperator result operator is not current supported" – NoloMokgosi Oct 02 '14 at 12:00

score 3 · Answer 2 · answered Jun 21 '11 at 18:44

3

Of your two choices the first options is better because it does 1 query. Second option will execute 2 queries.

answered Jun 21 '11 at 18:44

Todd

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Which one is better for getting the last row of my table with linq to nhibernate?

2 Answers2