Does linq to sql have a with ties option? - linq-to-sql

Question

I'm trying to move the following query to Linq-to-sql, is it possible?
select * from (
Select top (#Percent) percent with ties *
from(
Select distinct
LoanNumber as LoanNo
From CHE
Left Join RecordingInfo as Rec
On CHE.LoanNumber = Rec.LoanNo
Where Channel = 'LINX'
and CHE.Doc in ('MTG','MOD')
and Rec.LoanNo is null
and LoanNumber >= '#LoanNo'
) A
order by LoanNo #Order
) B
order by LoanNo
I have not seen anyway to do with ties in linq.

Answer 1

I think something like this will work for you.
public static IQueryable<T> TopPercentWithTies<T, TKey>(this IOrderedQueryable<T> query, Expression<Func<T, TKey>> groupByExpression, double percent)
{
var groupedQuery = query.GroupBy(groupByExpression);
int numberToTake = groupedQuery.Count() * percent / 100;
return groupedQuery.Take(numberToTake).SelectMany(t => t);
}
I only tested it with IEnumerable, so I don't know for sure that it'll work properly with IQueryable. I also sorted the list before calling TopPercentWithTies().
Here's the code I used to test it.
int percent = 50;
var people = new []
{
new { Age = 99, Name = "Adam" },
new { Age = 99, Name = "Andrew" },
new { Age = 89, Name = "Bob" },
new { Age = 50, Name = "Cecil" },
new { Age = 50, Name = "Doug" },
new { Age = 50, Name = "Everett" },
new { Age = 35, Name = "Frank" },
new { Age = 25, Name = "Greg" },
new { Age = 15, Name = "Hank" }
};
var sortedPeople = people.AsQueryable().OrderByDescending(person => person.Age);
var results = sortedPeople.TopPercentWithTies(person => person.Age, percent);
foreach (var person in results)
Console.WriteLine(person);
Hope it helps or at least gets you in the right direction. You may want to tweak the logic for calculating numberToTake.