Tag-and-role query with Linq / LLBLGen

gistfile1.cs

var tags = from tag in data.Tag
           join articleTag in data.ArticleTag on tag.Id equals articleTag.TagId
           join articlesWithRole in
               (
                  from articleTag in data.ArticleTag
                  join tagRole in data.TagForRole on articleTag.TagId equals tagRole.TagId
                  select new
                  {
                      ArticleId = articleTag.ArticleId,
                      Role = tagRole.Role
                  }
               ) on articleTag.ArticleId equals articlesWithRole.ArticleId
           where !( from tagRole in data.TagForRole
                    select tagRole.TagId ).Contains( tag.Id )
                    && tag.IsMainTag
           select new
           {
               Role = articlesWithRole.Role,
               Tag = new TagEntity
               {
                   Id = tag.Id,
                   Title = tag.Title,
                   Description = tag.Description
               }
           };