danared

var findNeighbours = function (spot, yearTag) {
  var result = db.postcodes.aggregate([
      {
        $geoNear:
        {
          near: spot,
          distanceField: "distance",
          num: 5,
          spherical: true
        }

danared

db.hottestLocations.findOne()
{
  "_id": ObjectId("5629108c96be45aba9cb0c98"),
  "Year": 2015,
  "PostCode": "SL6 9UD",
  "Location": [
    {
      "type": "Point",
      "coordinates": [
        51.558455,

danared

db.homeSales.aggregate([
    {
      $sort: {amount: -1}
    },
    {
      $group:
      {
        _id: {$year: "$date"},
        priciestPostCode: {$first: "$address.postcode"}
      }

danared

> db.homeSales.findOne()
{
  "_id": ObjectId("56005dd980c3678b19792b7f"),
  "amount": 9000,
  "date": ISODate("1996-09-19T00:00:00Z"),
  "address": {
    "nameOrNumber": 25,
    "street": "NORFOLK PARK COTTAGES",
    "town": "MAIDENHEAD",
    "county": "WINDSOR AND MAIDENHEAD",

danared

{
  "Year": 2015,
  "PostCode": "SL6 9UD",
  "Location": [
    {
      "type": "Point",
      "coordinates": [
        51.558455,
        -0.756023
      ]

danared

db.homeSales.aggregate([
    {
      $sort: {amount: -1}
    },
    {
      $group:
      {
        _id: {$year: "$date"},
        priciestPostCode: {$first: "$address.postcode"}
      }

danared

{
   "Year": 2012,
   "hightToLowPriceGap": 2923000
},
{
   "Year": 2013,
   "hightToLowPriceGap": 5092250
},
{
   "Year": 2014,

danared

db.annualHomePrices.aggregate([
  {$project: 
    {
      Year: "$year",
      hightToLowPriceGap: {
        $subtract: ["$highestPrice", "$lowestPrice"]
      },
      _id: 0
    }
  }

danared

> db.annualHomePrices.findOne()
{
  "_id": ObjectId("560957ac29a5574d557d426d"),
  "highestPrice": 1000000,
  "lowestPrice": 12000,
  "averagePrice": 114059,
  "priceStdDev": 81540,
  "year": 1995
}

danared

db.homeSales.aggregate([
  {
    $group: 
    {
      _id: {$year: "$date"},
      highestPrice: {$max: "$amount"},
      lowestPrice: {$min: "$amount"},
      averagePrice: {$avg: "$amount"},
      priceStdDev: {$stdDevPop: "$amount"}
    }