Get values as array of elements after $lookup

Question

For MongoDB, when using $lookup to query more than one collection, is it possible to get a values-only list for a field returned in the $lookup?

<

Answer 1

Just use .dot notation with the name field

db.foo.aggregate([
  { "$lookup": {
    "from": "bar",
    "localField": "name",
    "foreignField": "foo",
    "as": "bars"
  }},
  { "$addFields": { "bars": "$bars.name" }}
])

MongoPlayground