gistfile1.scala

private val postWithAuthor = Post ~< User

def allWithAuthor : List[Post ~ User] = 
   SQL("""select * from Post p 
          join User u on p.author_id = u.id """)
     .as(postWithAuthor*) 
    
def byIdWithAuthorAndComments(id: Long) :
      Option[Post ~ User ~ List[Comment]] = {

        SQL("""select * from Post p
               join User u on p.author_id = u.id
               left join Comment c on c.post_id = p.id
               where p.id = {id}""")
         .on("id" -> id)
         .as((postWithAuthor ~< (Comment*))?)

    }