Template
single collection
multiple collections
mgodatagen
update
indexe
explain
Stage
Database
bson
mgodatagen
[{userId:1,nickname:"a"},{userId:2,nickname:"b"},{userId:3,nickname:"c"}]
Query
db.collection.aggregate([{"$group":{"_id":null,"users":{"$push":"$$ROOT"}}},{"$set":{"newField":123456}}])
Result