Question

Lets say I have this table:

PetID    Name    Age    Weight 

How can I in a Linq2SQL get the name, age and weight of each pet that is the heaviest in its age group?

So if I have one pet of age 5 and four pets of age 2, I would like the Name, Age and Weight of the one that is age 5, and the one of the four with age 2 that is the heaveiest of those four.

This should probably not be too difficult, but I am not too into query thinking yet. Working on it though. And this is one kind of problem that I will need many times, but doesn’t quite manage to wrap my head around how to do…

I think it would include using the Max or a > operator, and some sort of grouping or joining, but thats about as far as I’ve gotten….

---

Thanks for the answers. All of them put me on the right track when it comes to the GroupBy stuff. The one I marked as an answer, was the one that was closest to what I ended up with.

Answer 1

It could be something like this:

var pets =  from pet in petSource             group pet by pet.Age into g             let max = g.OrderByDescending(p => p.Weight).FirstOrDefault<Pet>()             select new { Name = max.Name, Age = max.Age, Weight = max.Weight };