Question

I have some linq that returns the correct data.

var numEmails = (from row in EmailBatchProposal  
where row.EmailBatchId == emailBatchId
select row.EmailBatchProposalId).Count();

However, if I understand linq correctly, this does not perform optimally. It grabs all the data and then walks through the list and counts the rows. What I’d really like is for linq (in the background) to use like:

Select count(*) from ...

I trust the performance reasons are obvious.

Does anyone know the proper way to do this?

Answer 1

Actually, if the linq query is used with a collection that implements IQueryable and supports translation into underlying SQL variant, it is quite a basic functionality to translate the Count function from your example correctly.