As LostKobrakai, it’s actually a good feature that Ecto only does what you ask and performs no “guessing”.
You can avoid the extra query if you preload on a join, in this case Ecto is smart enough to know that comments has already been retrieved, because you’ve basically been explicit about what to get and how to get it.
from([post: post] in query,
left_join: comments in assoc(group, :comments),
as: :comments,
preload: [comments: comments]
)
This has the side effect that you could actually filter the comments in query but still get them “preloaded” for example.
