MongoDB Exercise - Look for restaurants in Manhattan or Brooklyn whose cuisine is not American or Chinese, and which have at least one grade lower than 5

Write a MongoDB query to find the restaurants that have at least one grade with a score of less than 5 and that are located in the borough of Manhattan or Brooklyn, and their cuisine is not American or Chinese.

Structure of 'restaurants' collection :

{
  "address": {
     "building": "1007",
     "coord": [ -73.856077, 40.848447 ],
     "street": "Morris Park Ave",
     "zipcode": "10462"
  },
  "borough": "Bronx",
  "cuisine": "Bakery",
  "grades": [
     { "date": { "$date": 1393804800000 }, "grade": "A", "score": 2 },
     { "date": { "$date": 1378857600000 }, "grade": "A", "score": 6 },
     { "date": { "$date": 1358985600000 }, "grade": "A", "score": 10 },
     { "date": { "$date": 1322006400000 }, "grade": "A", "score": 9 },
     { "date": { "$date": 1299715200000 }, "grade": "B", "score": 14 }
  ],
  "name": "Morris Park Bake Shop",
  "restaurant_id": "30075445"
}

Query:

db.restaurants.find({
    $and: [
        {
            $or: [
                {borough: "Manhattan"},
                {borough: "Brooklyn"}
            ]
        },
        {
            $nor: [
                {cuisine: "American"},
                {cuisine: "Chinese"}
            ]
        },
        {
grades: {
                $elemMatch: {
score: { $lt: 5 }
                }
            }
        }
    ]
})

Output:

{ "_id" : ObjectId("6422c0161238e3bec47ca601"), "address" : { "building" : "351", "coord" : [ -73.98513559999999, 40.7676919 ], "street" : "West   57 Street", "zipcode" : "10019" }, "borough" : "Manhattan", "cuisine" : "Irish", "grades" : [ { "date" : { "$date" : 1409961600000 }, "grade" : "A", "score" : 2 }, { "date" : { "$date" : 1374451200000 }, "grade" : "A", "score" : 11 }, { "date" : { "$date" : 1343692800000 }, "grade" : "A", "score" : 12 }, { "date" : { "$date" : 1325116800000 }, "grade" : "A", "score" : 12 } ], "name" : "Dj Reynolds Pub And Restaurant", "restaurant_id" : "30191841" }
{ "_id" : ObjectId("6422c0181238e3bec47ca607"), "address" : { "building" : "6409", "coord" : [ -74.00528899999999, 40.628886 ], "street" : "11 Avenue", "zipcode" : "11219" }, "borough" : "Brooklyn", "cuisine" : "American ", "grades" : [ { "date" : { "$date" : 1405641600000 }, "grade" : "A", "score" : 12 }, { "date" : { "$date" : 1375142400000 }, "grade" : "A", "score" : 12 }, { "date" : { "$date" : 1360713600000 }, "grade" : "A", "score" : 11 }, { "date" : { "$date" : 1345075200000 }, "grade" : "A", "score" : 2 }, { "date" : { "$date" : 1313539200000 }, "grade" : "A", "score" : 11 } ], "name" : "Regina Caterers", "restaurant_id" : "40356649" }
.....

Explanation:

The said query in MongoDB that searches for restaurants that are located in Manhattan or Brooklyn, have a cuisine that is not American or Chinese, and have at least one grade with a score of less than 5.

This conditions that enclosed in the square brackets after $and operator must be met in order for a document to be returned.

The $or operator specified that the restaurant must be located in either the borough of Manhattan or Brooklyn.

The $nor operator specified that the restaurant's cuisine cannot be American or Chinese.

The $elemMatch operator specified that the restaurant must have at least one grade with a score of less than 5.

Note: This output is generated using MongoDB server version 3.6

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