support read=false on paged contents query

[mydearxym]

when query read=true, i can use:

read == true ->
   queryable
   |> join(:inner, [content, f, c], viewers in assoc(content, :viewers))
   |> where([content, f, c, viewers], viewers.user_id == ^user.id)

but came to read=false, this is not work as except

read == true ->
   queryable
   |> join(:inner, [content, f, c], viewers in assoc(content, :viewers))
   |> where([content, f, c, viewers], viewers.user_id != ^user.id)

because the viewers assoc only have records of viewed user, the unviewed user is not in that table
left_join is not working either, need help...