[{"certnumber":"123456","createtime":ISODate("2024-02-03T16:42:20.324Z"),"company":"A"},{"certnumber":"123456","createtime":ISODate("2024-02-03T16:32:20.324Z"),"company":"A"},{"certnumber":"123456","createtime":ISODate("2024-02-02T14:28:20.324Z"),"company":"A"},{"certnumber":"123456","createtime":ISODate("2024-02-02T13:22:20.324Z"),"company":"A"},{"certnumber":"654321","createtime":ISODate("2024-02-05T17:42:20.324Z"),"company":"B"},{"certnumber":"654321","createtime":ISODate("2024-02-05T16:42:20.324Z"),"company":"B"},{"certnumber":"654321","createtime":ISODate("2024-02-03T15:32:20.324Z"),"company":"B"},{"certnumber":"654321","createtime":ISODate("2024-02-03T14:22:20.324Z"),"company":"B"}]

db.collection.aggregate([{"$setWindowFields":{"partitionBy":"$certnumber","sortBy":{"createtime":-1},"output":{"rank":{"$rank":{}}}}},{"$match":{"rank":1}},{"$unset":"rank"},{"$merge":{"into":"collection2"}}])