Linq. Filter Records

[shapper]

Hello,

I have the following Linq query:

viewData.PostsPapers = (from p in
database.Posts
select new PostPaper {
Post = p,
Tags = string.Join(", ",
(from pt in database.PostsTags

join t in database.Tags on pt.TagID equals t.TagID

where pt.PostID == p.PostID

select t.Name).ToArray())
}).ToList();

I need to get only the records that are associated to a Tag, given the
TagID or Tag Name.

I would like to know how to do this using TagID or using the Tag Name.

Could someone help me out?

Thank You,
Miguel