مرتب سازی بر روی آرایه با فهرست چند کلید

db.youstats.createIndex({ 
 "views.daily.data": -1      , // for Sort on maximum daily view
 commentsNumber: 1           , // for additional filter on comments
}); 

db.youstats.find({},{
  author: 1               ,
  title: 1                ,
  duration: 1             ,
  type: 1                 ,
  publishedDate: 1        ,
  commentsNumber: 1       ,
  // "views.daily": 1        ,
  // "day": 1                ,
}).sort({
  "views.daily.data": -1 
}).limit(3)

[
  {
    _id: 'ASO_zypdnsQ',
    commentsNumber: 1122436,
    author: 'officialpsy',
    publishedDate: '2013-04-13T11:59:04.000Z',
    title: 'PSY - GENTLEMAN M/V',
    duration: 234,
    type: 'video/3gpp'
  },
  {
    _id: 'My2FRPA3Gf8',
    commentsNumber: 1125301,
    author: 'MileyCyrusVEVO',
    publishedDate: '2013-09-09T16:00:38.000Z',
    title: 'Miley Cyrus - Wrecking Ball',
    duration: 222,
    type: 'application/x-shockwave-flash'
  },
  {
    _id: 'YoB8t0B4jx4',
    commentsNumber: 39370,
    author: 'SA Wardega',
    publishedDate: '2014-09-04T14:28:22.000Z',
    title: 'Mutant Giant Spider Dog (SA Wardega)',
    duration: 239,
    type: 'video/3gpp'
  }
]

  {
    _id: 'YoB8t0B4jx4',
    commentsNumber: 39370,
    author: 'SA Wardega',
    publishedDate: '2014-09-04T14:28:22.000Z',
    title: 'Mutant Giant Spider Dog (SA Wardega)',
    day: {
      data: [
        Long('1409788800000'), Long('1409875200000'), Long('1409961600000'), Long('1410048000000'), Long('1410134400000'), Long('1410220800000'), Long('1410307200000'), Long('1410393600000'), Long('1410480000000'), Long('1410566400000'), Long('1410652800000'), Long('1410739200000'), Long('1410825600000'), Long('1410912000000'), Long('1410998400000'), Long('1411084800000'), Long('1411171200000'), Long('1411257600000'), Long('1411344000000'), Long('1411430400000'), Long('1411516800000'), Long('1411603200000'), Long('1411689600000'), Long('1411776000000'), Long('1411862400000'), Long('1411948800000'), Long('1412035200000'), Long('1412121600000'), Long('1412208000000'), Long('1412294400000'), Long('1412380800000'), Long('1412467200000'), Long('1412553600000'), Long('1412640000000'), Long('1412726400000'), Long('1412812800000'), Long('1412899200000'), Long('1412985600000'), Long('1413072000000'), Long('1413158400000'), Long('1413244800000'), Long('1413331200000'), Long('1413417600000'), Long('1413504000000'), Long('1413590400000'), Long('1413676800000'), Long('1413763200000'), Long('1413849600000'), Long('1413936000000'), Long('1414022400000'), Long('1414108800000'), Long('1414195200000'), Long('1414281600000'), Long('1414368000000')
      ]
    },
    duration: 239,
    type: 'video/3gpp',
    views: {
      daily: {
        data: [
          2964062, 17799094, 19526335, 14604160, 9606241, 5959851,  4090643,  3419126,  2907521, 2626169, 2195691,  1518943,  1251086,  1128994,  958318, 861349,   785797,   628364,   506154,  564079, 445417,   474349,   498093,   589038,  444256, 363379,   329318,   313375,   333627,  335226, 354050,   322087,   239715,   228562,  213420, 201771,   213078,   247715,   228587,  183759, 168511,   169992,   199282,   326091,  347602, 335237,   290271,   242939,   223959,  219971, 249009,   277773,   279301,   220609
        ]
      }
    }
  }

db.youstats.find({},{
  author: 1               ,
  title: 1                ,
  duration: 1             ,
  type: 1                 ,
  publishedDate: 1        ,
  commentsNumber: 1       ,
  "views.daily": 1        ,
  "day": 1                ,
}).sort({
  "views.daily.data": -1 
}).limit(3).explain("executionStats").executionStats

...
  nReturned: 3,
  executionTimeMillis: 1,
  totalKeysExamined: 7,
  totalDocsExamined: 3,
...
    stage: 'LIMIT',
    nReturned: 3,
    limitAmount: 3,
...
      stage: 'PROJECTION_SIMPLE',
      nReturned: 3,
...
        stage: 'FETCH',
        nReturned: 3,
...
          stage: 'IXSCAN',
          nReturned: 3,
          keyPattern: { 'views.daily.data': -1, commentsNumber: 1 },
          isMultiKey: true,
          multiKeyPaths: {
            'views.daily.data': [ 'views.daily.data' ],
            commentsNumber: []
          },
          direction: 'forward',
          indexBounds: {
            'views.daily.data': [ '[MaxKey, MinKey]' ],
            commentsNumber: [ '[MinKey, MaxKey]' ]
          },
          keysExamined: 7,
          seeks: 1,
          dupsTested: 7,
          dupsDropped: 4
        }
      }
    }
  }
}

db.youstats.find({
  "views.daily.data": { $exists: true } ,
  "commentsNumber": { $lt: 1 } ,
},{
  author: 1               ,
  title: 1                ,
  duration: 1             ,
  type: 1                 ,
  publishedDate: 1        ,
  commentsNumber: 1       ,
  "views.daily": 1        ,
  //"day": 1                ,
}).sort({
  "views.daily.data": 1 
}).limit(3)