example mongodb aggregation

Example 1: how to write the aggragation in mongodb

> db.mycol.aggregate([{$group : {_id : "$by_user", num_tutorial : {$sum : 1}}}])
{ "_id" : "tutorials point", "num_tutorial" : 2 }
{ "_id" : "Neo4j", "num_tutorial" : 1 }
>

Example 2: MONGODB AGGREGATION tutorials

db.stocks.aggregate([
  { $match: { "price": 2000 } }
])

Example 3: MONGODB AGGREGATION tutorials

db.stocks.find().pretty()