Question

I have a linq query that is creating a list. I only want to use the second where clause if affiliationID != 0. Any tips?

var associations = (from a in ftjent.Associations
                    join ap in ftjent.AssociationProducts on a.AssociationID equals ap.AssociationID
                    where ap.Product.Name == productName
                    where a.AffiliationID == affiliationID
                    select new
                        {
                            a.Acronym,
                            a.AssociationID,
                            a.Name
                         }
                     ).Distinct().OrderBy(assoc => assoc.Acronym);

Answer 1

Compare affiliationId with 0, if it does not have a value the where will always evaluate to true and the second comparison will not be made:

var associations = (from a in ftjent.Associations
                join ap in ftjent.AssociationProducts on a.AssociationID equals ap.AssociationID
                where ap.Product.Name == productName
                where (affiliationId == 0) ||  a.AffiliationID == affiliationID
                select new
                    {
                        a.Acronym,
                        a.AssociationID,
                        a.Name
                     }
                 ).Distinct().OrderBy(assoc => assoc.Acronym);