aggregate.js

# HW 5.2
db.zips.aggregate([
  {$match: {$and : [{"state": {$in: ['CA', 'NY']}}]}}, 
  {$group: {_id: "$city", total: {$sum: "$pop"}}}, 
  {$match: {"total": {$gt: 25000}}}, {$group: {_id: 'kota', rerata: {$avg: "$total"}}}
])

{
  "_id" : ObjectID(),
  "name": "",
  "category": "",
  "manufacturer": "",
  "price": 0
}
{
  "_id" : ObjectID(),
  "name": "",
  "category": "",
  "manufacturer": "",
  "price": 0
}

db.orders.aggregate({
  {$group: {_id: "$manufacturer", total: {$sum: "$price"}}}
})

SQL: SELECT manufacturer, SUM(price) FROM orders GROUP BY manufacturer

db.orders.aggregate([
  {$group: {_id: {'manufacturer': '$manufacturer',
                  'category': '$category'},
            total: {$sum: 1}
           }
  }
])

db.orders.aggregate({
  {$match: {active: true}},
  {$group: {_id: "$cust_id", total: {$SUM: "$price"}}}
})

SQL: SELECT manufacturer, SUM(price) FROM orders GROUP BY manufacturer, category

db.orders.aggregate({
  {$unwind: "$items"}, {$group: {_id: "$cust_id", qty: {$SUM: 1}}}
})

SQL: SELECT cust_id, SUM(li.qty) FROM orders o, order