Chapter 2, Basic Joins: ForeignField, LocalField

Is there a reason we’re using match & pipeline with an expression vs. just simply referring to _id as the localField and movie_id as the foreign field? That seems significantly simpler to me, and it seems to work the same in Compass…

haha. Nevermind. Kept watching, and we’re looking for the count() on those. Hence the need for the pipeline, right?