Template
single collection
multiple collections
mgodatagen
update
indexe
explain
Stage
Database
bson
mgodatagen
[{"age":22},{"age":35},{"age":41},{"age":22}]
Query
db.collection.aggregate([{$group:{_id:"$age",users:{$push:"$$ROOT"}}},{$sort:{_id:1}},{$limit:1}])
Result