db.getCollection('Transaction').aggregate([ {"$group" : { "_id": "$transactionNo", "count": { "$sum": 1 }, "ids":{"$push":"$_id"} } }, {"$match": {"_id" :{ "$ne" : null } , "count" : {"$gt": 1} } } ])
db.getCollection('Transaction').aggregate([ {"$group" : { "_id": "$transactionNo", "count": { "$sum": 1 }, "ids":{"$push":"$_id"} } }, {"$match": {"_id" :{ "$ne" : null } , "count" : {"$gt": 1} } } ])