Template
single collection
multiple collections
mgodatagen
update
indexe
explain
Stage
Database
bson
mgodatagen
[{_id:0,file:"2020-05-06"},{_id:1,file:"2020-05-06"},{_id:2,file:"2022"}]
Query
db.collection.aggregate([{"$group":{"_id":0}},{"$project":{"_id":0,"file":1}}])
Result