def get_all_post_by_user(user_id) do
  query = from u in User,
     where: u.id == ^user_id,
      join: p in Post, on: p.user_id == u.id,
      select: %{
          user_id: u.id,
          username: u.username,
           title: p.title,
           description: p.description
      }
   query |> Repo.all
end

i have this query but when i try to render it, it returns multiple set of data but same User with different Post.
like this.
[

              %{user_id: 1,
              username: "saint",
               title: "test1",
               description: "sample1"},

              %{user_id: 1,
              username: "saint",
               title: "test2",
               description: "sample2"}
]

Thanks in advance.