I have an an offer, that can be in any number of categories. I don't however want that offer to then appear twice or however more.

I was wondering if its possible to have a where clause that ascertains whether that offer already exists in that select statement and if so obviously to ignore it.

Here is the linq query:

            Offers = from o in offerCategories
                     orderby o.RewardCategory.Ordering, o.Order  
                     where o.RewardOffer.IsDeleted == false
                     select new OfferOverviewViewModel
                     {
                         Partner = o.RewardOffer.Partner,
                         Description = String.Format("{0} {1}", o.RewardOffer.MainTitle, o.RewardOffer.SecondaryTitle),
                         OfferId = o.OfferId,
                         FeaturedOffer = o.RewardOffer.FeaturedOfferOrder.HasValue,
                         Categories = from c in offerCategories.Where(oc => oc.OfferId == o.OfferId)
                                      orderby c.RewardCategory.Ordering
                                      select new CategoryDetailViewModel
                                      {
                                          Description = c.RewardCategory.DisplayName
                                      }

                     },