Filtering

Question 1

Mongo DB:

Select records from collection where field1 equals value

Answer 1

db.collection.find({field1: value})

Question 2

MongoDB

Select records from collection where field1 greater than value

Answer 2

db.collection.find({field1: {$gt: value}})

Question 3

MongoDB

Select records from collection where field1 lower than value

Answer 3

db.collection.find({field1: {$lt: value}})

Question 4

Mongo DB

Select records from collection where field1 lower than or equal to value

Answer 4

db.collection.find({field1: {$lte: value}})

Question 5

Mongo DB

Select records from collection where field1 greater than or equal to value

Answer 5

db.collection.find({field1: {$gte: value}})

Question 6

Mongo DB

Select records from collection using and condition

Answer 6

db.collection.find($and: [{condition1}, {condition2}])

Question 7

Mongo DB

Select records from collection using regex

Answer 7

db.collection.find({field: {$regex: “pattern”}})

Question 8

Mongo DB

Select records from collection which have a given size

Answer 8

db.collection.find({field: {$size: value}})

Question 9

Mongo DB

Select records from collection which have a given field

Answer 9

db.collection.find({field: {$exists: true}})

Question 10

Mongo DB

Select records from collection which don’t have a given field

Answer 10

db.collection.find({field: {$exists: false}})

Question 11

Mongo DB

Select records from collection sorted by a given field ascending

Answer 11

db.collection.find().sort({field: 1})

Question 12

Mongo DB

Select records from collection sorted by a given field descending

Answer 12

db.collection.find().sort({field: -1})

Question 13

Mongo DB

Select records from collection limited by a given amount

Answer 13

db.collection.find().limit(limitCount)

Question 14

Mongo DB

Select records from collection skiped by a given amount

Answer 14

db.collection.find().skip(skipCount)

Question 15

Mongo DB

Select records from collection including specific fields only

Answer 15

db.collection.find({}, {field1: 1, fields2: 1})

Question 16

Mongo DB

Select records from collection excluding specific fields

Answer 16

db.collection.find({}, {field1: 0, fields2: 0})

Question 17

Mongo DB

How to filter records using nested values?

Answer 17

db.collection.find(“address.city”, “Mexico DF”)

Question 18

Mongo DB

How to filter using conditions?

Answer 18

db.collection.find(subject: “math”, score: {$gt: 90})

Question 19

Mongo DB

How to filter certain results of a given array from a specific document?

Answer 19

db.collection.find({_id: ObjectId(“your_document_id”), arrayfield: {$elementMatch: {field1: “value1”, field2: {$gte: 10}}}})

Question 20

Mongo DB

How to filter certain results of a given array from a all documents?

Answer 20

db.collection.aggregate([{$match: {arrayField: {$elementMatch: {field1: “value1”, field2: {$gte: 20}}}}}])

Question 21

Mongo DB

How to filter records from and array inside another array?

Answer 21

db.collection.find({“outerArray”: {$elementMatch: {“innerArray”: {$elemMatch: {field1: “value”, field2: {$gte: 10}}, field: “value”}}}})