M121

Connection string to 'aggregations' database

mongo "mongodb://cluster0-shard-00-00-jxeqq.mongodb.net:27017,cluster0-shard-00-01-jxeqq.mongodb.net:27017,cluster0-shard-00-02-jxeqq.mongodb.net:27017/aggregations?replicaSet=Cluster0-shard-0" --authenticationDatabase admin --ssl -u m121 -p aggregations --norc

##Template db.movies.aggregate([ { $match: { "year": {$gte:2017} } } ])

Chapter 1

Lab - $match

var pipeline = [{$match: {"imdb.rating":{$gte:7}, "genres": {$nin:["Crime","Horror"]}, "rated": {$in: ["PG", "G"]}, $and:[{"languages":"English"}, {"languages": "Japanese"}] }}]

db.movies.aggregate(pipeline).itcount()

Lab - $project

var pipeline = [{$match: {"imdb.rating":{$gte:7}, "genres": {$nin:["Crime","Horror"]}, "rated": {$in: ["PG", "G"]}, $and:[{"languages":"English"}, {"languages": "Japanese"}] }}, {$project: { _id:0, title:1, rated: "$imdb.rating" }} ]

Lab - Computing field

db.movies.aggregate([ { $project: { _id:0, title:1, numberOfWords: {$size: {$split: ["$title"," "]}} }

},
{$match: {
    numberOfWords: {$eq:1}
    }
}

]).itcount()

Chapter 2

Lab - Using Cursor-like Stages

db.movies.aggregate([ { $project: { _id:0, title:1, numberOfWords: {$size: {$split: ["$title"," "]}} }

},
{$match: {
    numberOfWords: {$eq:1}
    }
}

])

db.movies.aggregate([ { $match: { "countries": "USA", "tomatoes.viewer.rating": {$gte:3} } }, { $project: { _id:0, title:1, rated: "$tomatoes.viewer.rating"

    }
},
{
    $sort: {
        rated:-1,
        title: -1
    }
}

])

##Chapter 3

$group

db.movies.aggregate([ { $group: { _id: "$year", num_films_in_year: {$sum:1} } }, { $sort: { num_films_in_year: -1 } } ])

db.movies.aggregate([ { $group: { _id: { numDirectors: { $cond: [{$isArray: "$directors"},{$size: "$directors"}, 0] } } } }, { $sort: {"_id.numDirectors":-1} } ])

Lab- $group and Accumulators

db.movies.aggregate([ { $match: { "awards": {$regex: /Won\s\d{1,2}\sOscar/} } }, { $group: { _id: null, average_rating: {$avg: "$imdb.rating"}, deviation: {$stdDevSamp: "$imdb.rating"}, highest_rating: {$max: "$imdb.rating"}, lowest_rating: {$min: "$imdb.rating"}, total: {$sum: 1} } } ])

tuyendq/m121